M5 CSL

To celebrate 25 years of the M5, BMW has created a one-off version of the E60 super saloon that Albert Biermann, head of BMW's M division calls, "the M5 CSL we never built."

The transformation began with a modified version of the standard M5's 5.0-liter V10, which has been stroked to 5.5-liters and fitted with a carbon fiber intake, secondary oil cooler and a new fascia. BMW remains mum on official power figures, but Biermann says the mods are good for around 580 hp and 400 lb.-ft. of torque over the standard 507 hp engine.

Mated to the modified mill is a fortified version of the seven-speed dual-clutch Getrag gearbox fitted to the current M3, while a carbon fiber roof joins a set of lightweight, carbon fiber seats up front. That, combined with the removal of the rear seats, sheds around 110 pounds from the M5's curb weight.

Although performance stats haven't been released, BMW says the M5 CSL laps the Nurburgring around 20 seconds faster than the standard model, so something around the 7:50 mark isn't out of the question. What is out of the question is the opportunity to buy the CSL. BMW has no plans to offer it to the public!