MG ROVER has produced a performance upgrade for all ZT and 75 diesel models. The XPOWER upgrade, developed in association with the Sport and Racing division, gives power increases for the MG ZT CDTi from 113bhp to 128bhp, with peak torque up from 191lb-ft to 221lb-ft.

The enhancement improves performance in 0-60 times by one second to 10 seconds in the ZT CTDi, and by nearly two seconds from 50-70mph in fifth gear. These figures are mirrored across all models.

The package, which costs £490, must be fitted post-registration at dealerships, but its cost would be added to the P11d price of a car for benefit-in-kind tax purposes. However, as a retro-fit upgrade, the company car tax calculation is still based on the original carbon dioxide emissions of the car as registered on its V5 document.

MG Rover says because of the work done to the engine mapping, the upgraded car's fuel economy should stay the same and in some cases, particularly when driven gently, will improve.

Eventually, the firm is aiming to offer an XPOWER upgrade to all diesel MG and Rover cars.