Q: It makes very little sense to me why a high-performance car like the M3 does not have any form of forced induction. A V8 with turbos or supercharger can easily get 500 HP so is BMW holding out on purpose? Having forced induction just means that you can increase and maintain the optimal stoichiometric combustion ratio. This is independent of all other variables except excess heat. I am going to stick to my 335i for now and ramp up to a ferarri in a few years. If the Bugatti Veyron has quad-turbos then FI can't be that bad!!!
A: To date, an M car has yet to be turbocharged. They're thinking about switching the M5 to a TT V8, but i hope they don't. Efficiency and cost has nothing to do with it - it's more of a Tradition basis. It's just not their style. They've only done a few factory turbo (petrol) cars, and their most recent one has been a maintenance disaster. The old 745i Turbo and the 2002 Turbo were good, though.