Not so with the Z4. Edgy design is married to great performance and true driver appeal. So there seems little reason to meddle and at first glance it seems little has changed with the refreshed 2006 Z4 range.
Aficionados will spot the new headlights and foglights, while the rear lights have had some minor changes. The front and rear bumpers have also been slightly tweaked.
Subtle is the word.
The major changes have taken place under the bonnet, with new additions being lowered into the engine bay.
First up, the old 2.2 and 2.5-litre units are retired as they do not comply with Euro IV emission regulations. In comes the all-new 2.5-litre straight-six engine in two power outputs, as well as BMW’s lightweight 3.0-litre six-pot engine (both already used in the new 3-series).
The standard 2.5i kicks out 177bhp and 170lb-ft of torque, while the more powerful 2.5si ups the stakes to 218bhp and 184lb-ft of torque. The 3.0-litre engine is only available in one state of tune and pumps out 265bhp and 232lb-ft.
The good news is that the 2.0-litre, four-cylinder version is retained as the entry-level model. With CO2 emissions of 181g/km, a performance of 0-62mph in 8.2 seconds as well as a top speed of 137mph, and prices starting at under £23,000, it’s not hard to see why BMW is predicting that half of Z4 sales will be the entry-level engine.
There is the option of a new version of the SMG semi-automatic transmission with both sequential changes at the gearstick and paddleshifts mounted behind the wheel, or you can have a full auto mode. Otherwise, standard across the range is the six-speed manual.
There is a new Sport specification for all variants, with the key difference that the ride height is lowered by 15mm, though this Sport kit is optional on other models.
But the Z4 M roadster, which is powered by the same 343bhp 3.2-litre straight-six engine that drives the current M3, wears the brightest performance halo.
It also borrows the M3’s brake set-up.
Surprisingly, the Z4 M is not offered with paddleshift gear change even though the M3 is, so it’s six-speed manual only.
Looks-wise, the Z4 M gets unique 18-inch wheels, bigger air ducts hanging from the front bumper, which means no forward foglights, and at the rear a pair of twin exhaust barrels aiming up from under the bumper.
Behind the wheel
WE tested two versions – the 2.5si and the M roadster. The M roadster is extremely rapid, which is not surprising given its ability to go from 0-62mph in five seconds dead.
It is the way the M uses its 343bhp that makes it so quick. While there is no huge grunt low down, as soon as the rev counter sweeps past 2,500rpm the power builds in a relentless surge all the way round to the redline.
You always have a ready source of power under your right foot and the close-action, six-speed gearbox is a joy to use.
The steering wheel pours feedback into your hands and the 2.5si feels more agile and pinpoint accurate in plotting a line through corners. Gear selection is more critical if you want to keep rapid forward motion.
The smaller-capacity Z4 drives with more finesse compared to the Z4 M roadster, and will probably be as quick point-to-point despite its power deficit. The difference is that the M version has more of a sledgehammer approach, with its massive mid-range punch driving the car hard out of corners.
The electronic stability programme is uprated to include new, useful driver aids such as hill start assist that keeps the brake on as you transfer from foot brake to throttle.
The others include keeping discs dry in wet weather, priming them for expected emergency stops, adjusting the brakes to help avoid any fade and ensuring the car stops gently when coming to a standstill.
The driving position is as before, with the M Sport seats proving particularly supportive, though with the roof down wind buffeting is very noticeable even with the wind deflector fitted.
THE Z4’s new engines and tweaks enhance its driver appeal as a drop-top sports car.
The new 2.5si delivers an exhilarating drive with more accurate handling than the M version, which provides more of a raw driving experience – inexperienced drivers should keep the DSC stability control on.
The Z4, especially the M version, is now an even more compelling alternative to the Porsche Boxster.
|Max power (bhp/rpm):||150||177||218||265||343|
|Max torque (lb-ft/rpm):||147.5||170||184||232||269|
|Max speed (mph):||137||142||149||155*||155*|
|Fuel consumption (mpg):||37.7||34.4||33.6||32.9||23.3|
|CO2 emissions (g/km):||181||197||202||207||292|