The G is a fine car and if you can afford only one car at a time it's really a better choice for more than day-to-day operations.
You know when you need more comfort, more room/seats, haul stuff and people around etc.
That said, I have a four door Altima SE-R that does that job for me. It's friggin huge inside. The back seat leg room whatever seems to have more room than the Z's front. Had it since new and I love to run the hell out of it. It's not a G but still a fun car to drive and is surprisingly fast. Paid for years ago too..
If you can afford two cars keep your Z for your day-to-day stuff like doing burnouts and scaring old ladies (giggle) and purchase a late model something to haul people and stuff around when you need to. Or...just get a G?
lp