FWIW, Audi S3 is also primarily FWD via Haldex and not true Quattro. Any horizontally oriented Audi/VW engine has crap AWD. The longitudinal engines get real Quattro, such as the S4. But back to BMW, I'm skeptical on what a tune/mods will due to the F80 M3. The S55 is already going to be pretty spiced up and having to manage a lot of heat issues. They better have a serious IC setup and optimize air flow. We've all seen that engine bay and it is CRAMPED in there. All in all though, we really have to wait for specs and dynos.
I'm still trying to figure out why ///M didn't start with a 3.2 or 3.3L I6. Too much work for them I guess.