My experience with the SMG in 2005 M3 was lukewarm. We had both SMG and 6 spd in almost identical M's, I like the Audi manual tranny much better than either choice from BMW.

2007 RS4, Misanored, Ebony, Prem, Milltek Res non-valved
2005 BMW X5 4.8is
2007 Honda Ridgeline RTL
Cayenne Turbo S on indefinite hold!