E90/E92 will likely be the last naturally aspirated models. Own a classic vs own a higher performing turbocharged model.

M3 may not be introduced at the same time as the 2012 3 series, it has been introduced later with previous generations.

Then there are all the issues related to owning the first year of a new model. I'd wait for year two myself, which means that it would be your replacement for a current M3.

__________________
2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue