Originally Posted by xxe92xx
turbocharging has ALOT more variables to consider...turbocharging a high compression engine isnt easy....BUT horsepower freaks developed a kit for the E46 M3 and i imagine there will also be a kit for the E90 M3 down the road...lots of R&D is required for a reliable kit
(why the sigh? is this a much asked question?)
I would be surprised if they didn't at least fit a thicker gasket to drop compression for turbocharging. I can't see a situation where they'd want to leave it as high as it is with the engine in normal form. Other than that I'm not aware of any extra variables over S/Cing a non-FI engine. Both present fuel, space and cooling issues. Both require a remap (most likely).
Not sure of the economics but possibly the economics of S/C are more favourable than Turbo. Also, it's possible that space plays a factor in our specific engine bay.