FORGET thirsty petrol engines, oil-burning models are now the pick of the range when it comes to executive cars. But which of the challengers will find favour with fleets?

Due to their size and weight, increasingly the best choice in a large executive car range is the big diesel-engined version. Certainly that's the case with the Mercedes-Benz E-class and the new BMW 5-series.

Because of the dimensions of the cars, the occupants can be well insulated from any diesel clatter emanating from under the bonnet, while the heave of torque available will make light work of the mass of the car.

The new 5-series has one of the most acclaimed diesel engines in the world, so the 530d should be the star performer on the road, especially when allied to its class-leading chassis. While its looks will take time to get used to, most will find that once seen in the flesh, it is much better looking than pictures suggest.

At the moment, leasing companies seem to be taking a conservative approach to its residuals, although this is likely to change as the public realises it is not half as radical as they have been led to believe.

Everybody already knows about the Mercedes-Benz E-class, and the mid-range E270 CDI Avantgarde combines refinement and efficiency wrapped in a classy package with a plush interior. Assuming the mantle of RV leader once the old 5-series started to make its exit, it will be challenged strongly by the new Five. A company car driver choosing between the BMW and Mercedes-Benz really cannot go wrong. Except that not everybody wants one of these two headline-grabbing cars.

Generally, the default option after that pair has been the Audi A6. It is now rather long in the tooth, but it means that for the money, a driver can get the top-of-the-range model with four-wheel drive and a Tiptronic gearbox for less cash than the BMW or Mercedes-Benz. Unfortunately the engine is only 2.5-litres and it could struggle with its residual value, which could impact on contract hire rates.

If a driver wants to avoid one of the quintessential German saloon triumvirate, there are some interesting alternatives. Alternative is the basis of the Renault Vel Satis. It looks odd but don't let that hide the fact this is a very clever car.

There is more space than any of the competitors here can muster and plenty of modernist style inside, although it might take a leap of brand faith for some to opt for a Renault at this price.

Volkswagen has come up with a winning formula with the Touareg. Hefty, with huge presence and well-built, it is the latest in a line of off-roaders with good dynamics to challenge the saloon/estate hegemony at this price level. The 2.5-litre diesel engine might struggle in such a big vehicle, though.

The Volvo XC90 is car with a growing queue of potential suitors, and has a year-long waiting list to prove it.

Not as well built as the Touareg, or as big, but it does have seven seats. It has the smallest engine of the six here, and very high residuals, but is this artificially high due to its scarcity?

Andy Brown
Operations director, Inchcape Fleet Solutions
'This selection of cars puts the progress of diesel technology over recent years into sharp perspective. In a number of prestige models the pick of the range now has a diesel under the bonnet. The high torque, low rev nature of the engine is ideal, if noise levels can be controlled, for large saloons and off-roaders alike. There is also the added bonus of improved fuel economy and generally lower CO2 emissions.'

Andrew Cope
Managing director, Zenith Vehicle Contracts
'Diesel has now established itself as an attractive option for all levels of the company car market. The expansion of the upper level choice has removed the need for executives to drive a petrol- guzzling monster. Instead they are able to opt for its diesel brother which provides tax-efficient CO2 emissions. With this expansion, car makers have also created more and more attractive and cost-effective 4x4s.'

Tracy McMahon
Pricing manager, Lloyds TSB autolease
'This month's survey considers posh diesels. Due to changes in taxation, drivers are increasingly opting for these cars. There are a variety of models in this survey and these will appeal to customers who are looking for either driveability, practicality and/or style, for which I would choose the Mercedes-Benz E-class. A few of the cars even have more than one of these attributes, although the Volvo wins on practicality.'

Richard Schooling
Commercial director, Alphabet
'On current progress, the UK's executive car market could be 80% diesel by 2006. Fashion and terrific products, rather than benefit-in-kind tax benefits, seem to be driving executive diesel sales, even counting the impending BIK advantages of Euro IV emission compliant diesel engines. Future residual values? A lot depends on the current television adverts designed to increase diesel's appeal to private motorists.'

John Pout
Head of UK & international sales development, Arval PHH
'Overall it is hard to challenge BMW as the pick of the bunch in this sector. Expectations get higher year on year though, and all of these vehicles have moved the definition of quality to a higher plane. In the end though, it remains a toss-up between the Mercedes-Benz and BMW and it really comes down to a matter of taste – the next six months will see company car drivers decide which one has hit the spot.'

Vital statistics: how our models compare

Average rental rates
VW Touareg 2.5 TDI £585
Mercedes E270 CDI £599
Volvo XC90 2.4 D5 £600
BMW 530d £605
Audi A6 2.5 TDI £635
Renault Vel Satis 3.0 dCi £669

  • Average based on results from our leasing panel

    Average maintenance costs (3years/60,000 miles)
    BMW 530d £1,945
    Audi A6 2.5 TDI £2,414
    Mercedes E270 CDI £2,583
    Renault Vel Satis 3.0 dCi £2,583
    VW Touareg 2.5 TDI £2,650
    Volvo XC90 2.4 D5 £2,721

  • Average based on results from our leasing panel

    RV forecasts (3years/60,000 miles)
    Volvo XC90 2.4 D5 £13,339/41%
    VW Touareg 2.5 TDI £11,839/40%
    Mercedes E270 CDI £12,435/39%
    BMW 530d £11,721/36%
    Audi A6 2.5 TDI £8,011/26%
    Renault Vel Satis 3.0 dCi £7,048/23%

  • Average based on results from our leasing panel

    CO2 Emissions (g/km and tax band)
    Mercedes E270 CDI 180/23%
    BMW 530d 208/28%
    Renault Vel Satis 3.0 dCi 232/32%
    Audi A6 2.5 TDI 243/35%
    VW Touareg 2.5 TDI 273/35%
    Volvo XC90 2.4 D5 242/35%

  • Source: Vehicle Certification Agency (2003/04 tax year)

    Combined mpg
    Audi A6 2.5 TDI 31.4
    BMW 530d 36.2
    Renault Vel Satis 3.0 dCi 32.5
    Mercedes E270 CDI 41.5
    Volvo XC90 2.4 D5 31.0
    VW Touareg 2.5 TDI 28.0

  • Source: Vehicle Certification Agency

    Audi A6 2.5 TDI quattro SE 180 Tiptronic

    ##A6TDIcontract--none##

    Cope: 'The A6 has always been a solid option as it is reasonably priced with a high specification. Its well-established look and placid drive will soon replaced by a new model early next year.'
    Schooling: 'A6 has real Audi quality. Unfortunately, the Tiptronic quattro doesn't quite meet Euro IV standards, presenting drivers with a tax bill 80% higher than the front-wheel drive Multitronic version.'
    Brown: 'The build quality is second to none. The A6 works best as an estate and the lower-powered Multitronic version offers a much better tax proposition without compromising too much on performance.'
    Pout: 'Still a good-looking car even if it is a bit long in the tooth. Excellent interior layout is a key feature while road-holding is nearest to a 4x4 in feel. Might not want an honest fight with a 530d at the traffic lights, but it is smooth, trusty, and safe.'
    McMahon: 'The A6 is looking dated but the new model is due next year. The rentals are the second-highest as the model is coming to the end of its lifecycle, lowering residual values.'

    Average monthly rental £635
    P11D price £30,420
    Average net price £27,243
    Average maintenance £2,414
    Average RV £8,011/26%

    Rental Rates
    Inchcape £666.09
    Zenith £612.85
    Alphabet £643.14
    Arval PHH £631.00
    Lloyds TSB autolease £621.68

    2003 CO2 BIK tax bill (22%/40%): £2,342/£4,259
    2003 VED bill: £165

    BMW 530d SE auto

    ##530Dcontract--none##

    McMahon: The new 5-series looks the part and has more rear space than its predecessor. The CO2 emissions are low for this sector and the fuel economy is reasonable. It's the quickest here with a 0-60 time of 7.8 seconds.'
    Brown: 'Early reports are positive, and the i-Drive system is much simpler than that seen in the 7-series. The distinctive styling may be a shock to some more conservative buyers but it has the kudos of the BMW badge.'
    Pout: 'Lots of anticipation for this car and a relief to see it has raised the standard higher while retaining the classic good looks. The leader in this sector, everything about this car speaks of quality and attention to detail.'
    Cope: 'The radical looks of the 5-series could be off-putting to established drivers, but once behind the wheel the quality of drive and performance removes any hesitation. It will be interesting to watch the take up of this model.'
    Schooling: 'Has BMW made the best driving experience in the executive class even better? Yes, especially when BMW's ground-breaking £750 fixed cost servicing package is reflected in the rental price.'

    Average monthly rental £605
    P11D price £32,120
    Average net price £29,721
    Average maintenance £1,945
    Average RV £11,721/36%

    Rental Rates
    Inchcape £592.62
    Zenith £658.25
    Alphabet £564.01
    Arval PHH £588.00
    Lloyds TSB autolease £619.71

    2003 CO2 BIK tax bill (22%/40%): £1,979/£3,597
    2003 VED bill: £165

    Mercedes-Benz E270 CDI Avantgarde auto

    ##E270contract--none##

    Schooling: 'Some people won't put the Mercedes-Benz first for outright driver appeal but its impeccable finish and advanced safety credentials have been hailed as a true return to form.'
    Cope: 'This is the best value for money of the range with comparable performance to the E320. The CO2 performance makes it a sensible choice, and overall it is a solid and refined model.'
    Pout: 'This is still the car for the elegant sophisticate and prior to the appearance of the 530d would be most people's choice as sector leader. It drives exceptionally well and the Avantgarde trim adds some unexpected Germanic flair to the interior.'
    Brown: 'Far more elegant than the old car and much closer to matching the BMW in overall appeal. The E270 delivers an excellent compromise between performance and economy, while the overall refinement and intelligent cabin layout add to the appeal.'
    McMahon: 'The E-class is the prettiest and most sophisticated car in this sector, enjoyable to drive and with a classy interior. Earlier problems with electrics have been resolved.'

    Average monthly rental £599
    P11D price £31,980
    Average net price £29,329
    Average maintenance £2,583
    Average RV £12,435/39%

    Rental Rates
    Inchcape £612.55
    Zenith £612.90
    Alphabet £597.22
    Arval PHH £578.00
    Lloyds TSB autolease £594.19

    2003 CO2 BIK tax bill (22%/40%): £1,618/£2,942
    2003 VED bill: £155

    Renault Vel Satis 3.0 dCi Initiale auto

    ##Satiscontract--none##

    Brown: 'A comfortable, well-equipped cabin but the styling does it no favours. Obviously finding it difficult to succeed at a price level where brand and image feature highly. The Espace offers a far better package.'
    Schooling: 'It is brave of Renault to enter an inspirational car in an aspirational class. In more confident economic times, the Vel Satis would probably have found quite a few more customers.'
    McMahon: 'The Vel Satis has the most expensive rental caused by poor residual values. It's not the most sophisticated car in this survey, although equipment levels are excellent. Leather and satellite navigation come as standard.'
    Pout: 'It might be distinctive, but it's not everyone's idea of beauty. Nevertheless, there's plenty to please and for the non-badge devotees it is a quality alternative that dares to be different.'
    Cope: 'Renault has once again used bold modern design to try and break into this end of the market. Unfortunately its looks are too extreme for this refined sector, and many will be concerned at paying £30,000 and driving a Renault.'

    Average monthly rental £669
    P11D price £30,070
    Average net price £27,314
    Average maintenance £2,583
    Average RV £7,048/23%

    Rental Rates
    Inchcape £682.59
    Zenith £684.35
    Alphabet £666.97
    Arval PHH £642.00
    Lloyds TSB autolease £671.54

    2003 CO2 BIK tax bill (22%/40%): £2,183/£3,969
    2003 VED bill: £165

    Volkswagen Touareg 2.5 TDI auto

    ##Touaregcontract--none##

    Pout: 'This 4x4 seeks to please the estate driver and the off-roader and although it is eager to there's not enough guts under the bonnet to to really shift this relative heavyweight. Residuals will undoubtedly be strong as the small numbers will ensure desirability.'
    Brown: 'Sister-car to the Porsche Cayenne and much better looking. The Touareg performs very well off-road, which adds credibility. Slightly cumbersome on the Tarmac and the interior layout is cluttered.'
    McMahon: 'Smooth styling disguises the fact that this is a big car. The rentals are the lowest in this sector. However, CO2 levels are one of the highest, which means it is not necessarily the perfect company car choice.'
    Schooling: 'SUV residual values are holding up. That's good, since front-end prices have risen relatively fast over the last two years. The Touareg looks classy and won't disappoint on wholelife costs.'
    Cope: 'The launch of this new VW 4x4 has sent the company car world into a spin. Favourable reports on this vehicle's performance (both on and off-road) and pedigree have made it an irresistible option.'

    Average monthly rental £585
    P11D price £29,800
    Average net price £28,154
    Average maintenance £2,650
    Average RV £11,839/40%

    Rental Rates
    Inchcape £626.64
    Zenith £590.30
    Alphabet £560.55
    Arval PHH £569.00
    Lloyds TSB autolease £579.18

    2003 CO2 BIK tax bill (22%/40%): £2,295/£4,172 2003 VED bill: £165

    Volvo XC90 2.4 D5 SE Geartronic

    ##XC90contract--none##

    Schooling: 'Volvo has found a niche within a niche with the XC90. Drivers like its look and feel – less of a muscular off-roader, more like a road car that's taken up orienteering.'
    Pout: 'Plenty of room to spread yourself around with an extremely accommodating seating layout. Has Volvo's typical solid and safe qualities, supported by excellent wholelife costs. The 2.4 D5 struggles when fully loaded but pound-for-pound great value and versatility.'
    Brown: 'A runaway success, creating high showroom traffic. It has a broad spread of abilities and boasts excellent interior flexibility and class-leading ergonomics. Probably the best package here and worth a look.'
    Cope: 'Volvo has pushed itself to the fore in creating a good all-round car. The Volvo style has been further enhanced, attracting attention. Those who are tempted by this car will have to be patient, with lead times of 12 months.'
    McMahon: 'Volvo has been clever when designing the XC90, producing a combination of style and practicality, and has even found the space for seven seats. The rentals are excellent and the only downside is the waiting list, currently it is about nine to 12 months.'

    Average monthly rental £600
    P11D price £32,215
    Average net price £29,955
    Average maintenance £2,721
    Average RV £13,339/41%

    Rental Rates
    Inchcape £586.59
    Zenith £610.02
    Alphabet £605.80
    Arval PHH £611.00
    Lloyds TSB autolease £588.71

    2003 CO2 BIK tax bill (22%/40%): £2,481/£4,510
    2003 VED bill £165