I've owned 3 Zees, they're major fun to drive plus they're a chick magnet! You're young, why would you need an extra back seat? Only time you'll need a back seat is when you're married with children! Then you'll have a granny sedan unless you're smart enough to make a coupe work.
Gary

 

If you're giving a ride for your family then G35, family first!
But if it's friends, get the Z. With the G coupe they'll just be complaining about the lack of space in the back. And people are users.
And girls will like both of them, more of a lean on the Z. The girls in my area are pretty basic, and they think my black 06 sedan is nice, huge plus for me!

And thats an amazing shade of blue. I prefer that much more. Really makes you stand out. Reel in even more girls

 

Yeah that is true I could care less about 4 seats now that I think about it. I would get the gorgeous blue Z in a heartbeat over the G (no offense) but the only thing holding me back from it is that it's a base. No leather, no tcs, no gps. And the G has all of that. Would you still get a base Z over it?