I'm surprised to hear people saying they prefere the styling of the Z over the G. I know it happens, but everyone I know loves the look of the G over the Z, plus, the fit and finish is hands down in another league. Having driven the Z, I knew it would be a car that squeaked, rattled, and would probably have broken plastic somewhere within a year. For what amounted to about $2K difference between the 05 G and 05 Z Touring, it wasn't worth it. As noted above the 05 G and 05 Z Track were about the same price for virtually identical performance.

 

you should check out my350z, there is a good amount of threads with people discussing their switch from a Z to a G. The flow is overwhelmingly from a Z to a G, these threads will given you reasons why.

 

There are many trading from the Z to a G. not many I've heard about trading the other way.
You'd miss the practicallity of the G, not to mention the comfort, room, and beauty.
It's up to you but I wouldn't do it. The Z is a nice 2 seater, but the G in either config. is better.