I would stay away from 19's 20's just for weight reasons.18's can be had with reasonable weights.
We have some excellent wheels suppliers on this site as sponors be sure to check them all out.
I am also looking at wheels right now here is a similiar thread in the Nico 350Z forum:
http://nicoclub.com/zerothread?id=88818
Albeit my car is blue not red, but thats also a strong primary color and might influence wheels choices in the same direction.
I dont want to add any more color to my car and will probably go with flat silver (like the Nismo LMGT4's) or chrome (if not too heavy)wheels.
Alan from SPL has a nice 5zigens in stock that are light and look good I like them he posted them in that thread I linked.
Fred..