As someone who has had both, I can say (from first-hand experience) the GTO is a totally different kind of performance car. More raw and emotional; my 04 A4 (with a semi-custom tune) was an absolute blast to drive. With the "torque management" squelched by the tune, this car was a beast. Not the smooth, composed and seemingly relaxed attitude of the 335. I paid just over $23,000 brand-spanking-new for my 2004 GTO in Sept. of 2004... talk about bang for buck. No, it isn't near the complete car the 335i is, but it was also half the price. Lot's of folks around here (not all, but many) like to "paper" race. Go drive a GTO and then talk about how slow they are.
BTW, I also did a Monaro conversion on mine. Front facia, wheels, even emblems (inside and out). I was at the Infiniti/Porsche/Audi dealership (wife wanted to look at a G35 coupe) and after about 30 minutes a crowd formed around my "Holden Monaro CV8."