I think the REAL comparison would be between the new G35 COUPE (2 door) versions of the G35 versus the Bimmer 3-series.
I've driven the 330CI, and its a nice ride. IMO one of the benchmarks in "sporty small coupes".
I believe the G35 coupe has a power advantage, and better ergos/interior. Whether this offsets the fun factor and control of a manual tranny is going to be interesting.