OK, I'm only speculating based on the bits of information I've gathered from the media.

The E90 M3 is coming with a V8 engine, probably producing around 400hp. The 330i Turbo, although not acknowledged for production yet, will probably have a 3.0 Liter I-6, producing 300 hp.

I am guessing that the M3 will cost a leg and an arm, but the turbo 330i will not be a cheap car either. On the other hand, it could definitely fill the gap between the 258hp and 400hp, which is quite a gap.

I don't know if the Valvetronic engine can be successfully turbo charged as it's been supercharged by Alpina (although expensive and complicated, requiring special craftmanship for a small number of engines that's being produced in a 'workshop'). I'm not very familiar with turbo charging, but if reliability is an issue, I'm guessing that it's not just plug-and-play or is it ?

On the performance side, I'd say that they will be quite close to each other, in terms of accelaration and overall performance throughout the rpm range.

OK, other than just a game of hp numbers, what purpose will a 330i Turbo serve ?

What do you think ?

And those who would willing to spend the money on an M3, would they consider the Turbo instead ? I know it's too early to be able to say, but what the heck