If you read the marketing on the new Turbo six(see link below), BMW itself is saying how superior it is to a V8. Makes me wish that BMW was making an M version of that engine with 400-440 HP and 400 Lbs. of torque rather than the rumoured V8, with 400-440 and 320-350 Lbs of torque for the new M3(I have one on Order). According to BMW itself why would you want a V8 when the 6 is perfectedly balanced is 150 lbs less and better on gas and has no lag.
It will be interesting to see how BMW justifies the new M3 V8. Who knows maybe they are pulling a fast one on us, and BMW's reference to a range of six cyclinder Turbo's means the next M3 will have a Turbo 6. Unlikely as M says they like High revving low torque motors. But they also said they would only do SMG's and manual's are coming this fall in the M5 and M6.
Other than it doesn't meet the M Philosophy(although there is no reason you couldn't build an 8,000 RPM Twin Turbo Straight Six based on the Current M3 Motor), I think I would actually prefer an M version of the 335 motor. The extra Torque would be nice.
Thoughts? Who would prefer an M3 with a turbo Six over an eight? Although if the M3 has a flat plane V8 that would be pretty special as well.