S2K, 350z, G35 - you can't go wrong. All are nice and requires a bit of money to mod (350z and G35 costs a lil more, trust me, I know, I own a G).

Between a G and Z, I choose the G because I need backseat, and the G is much more classy upper class. The G is a lil heavier, so handling and power is a lil less compared to the Z. But it has more pros to outweight the cons. Nothing a lil power adder and full race suspension setup.

But each car is different. So one G may win against the Z, and lost against the other. My G dynoed better than some Z with similar mods. It's also the driver's game.