Hartge has come up with a new engine tuning package for BMW’s 4.4 liter twin-turbo V8 that powers the M5 and M6 (and also the M versions of X5 and X6). It boosts the power from the standard 560 hp to 642 hp, with over 810 Nm of torque.

That is a substantial increase in power, but the effect it has on the performance is not that significant. It drops the 0 to 100 km/h time to 4.2 seconds, and because Hartge has removed the top speed limiter, it can now go past 300 km/h. So unless you are planning on using your M5 or M6 for drag racing, it won’t make that big of a difference.

Hartge also offers a nice visual treatment for the M5, with a unique front spoiler, carbon mirrors, lowered suspension, and a wide rage of Hartge 21-inch wheels. They can also hook you up with a sport exhaust system.