If it's torque you're after, employ an N57!
The feeling of it in my 330d is addictive, and real fun! Made the 328i (F30) feel pathetic, although it is marginally pathetic. I wanted a 330d or 335d but the 328i was the closest regarding power and economy.
Yep, new M3 will be a completely different yet still absolutely beast. Wonder where the redline will be situated...