I've had several 280ZX cars. A 1979/81/82/83 and a 300 ZX. They all had way more room than the Crossfire. Never sat in a new 350Z, but I wouldn't think the interiors would be any smaller. That being said, I'm 6' 2", 215lbs, and like Nick, I too think my Crossfire fits just fine, with no claustrophobia.
I used to drive the Z's in a more laid back, arms out driving position. But I found the more upright position in the Crossfire to be more comfortable, and I discovered I don't have the neck pain that I used to get in the Z's after a long drive.