PANI K : Yep, Dinan stuff is extremely expensive, but that's because they're one of the only American Companies who deal entirely with BMW Cars, and extensively test everything they produce. But at the end of the day, the M5 had an aftermarket exhaust system, Air Intake Boxes and Filters, and a re-map.........which on a naturally aspirated car like the M5 (Which is already very hightly tuned by BMW M Sport) adds a maximum of 30bhp (As Quoted by Dinan). So the E39 M5 still did really well against BMW's latest M Power car.

In "BMW CAR" Magazine last month, they did exactly the same test (Standard v Standard) and again the E39 M5 came into it's own in the mid range acceleration tests. Yes.......the M3 is quicker, but by less than 1 second on most acceleration runs.......(0 - 60mph, 50 - 100mph and 100 - 155mph). No doubt that the M3 would certainly be the winner on track, but on the road, there is very little difference.