Well, I have driven both the g35 and the 350z on several occasions. ( I am a Nissan salesman ) The 350z has 7 more hp, and rides like a true sports car. The g35 has a softer suspension and a clock on the dash. ( main differences in the cars ) The 2 seats in the back of the g35 are only good for midgets and 5 year-olds. Also the spoiler on the g35 looks like a$$. Not worth the extra 5-6000 dollars.IMO
I find myself in your situation though, in that I will be buying a cobra or a 350z within the next 10-12 months. I just can't decide which.