I also thought about the 18/20 combo. now I really think I want to get 18x8 fronts and 20x10 rears. but I think I'll get the Coys C5 because the 20x10 version got a deeper lip than the Boss 338.
here some other G-Bodys with the 18/20 combo:
I really like this (you can see the deep lip or the rears):
here's my photoshop of that last pic (lowered front):
here some other G-Bodys with the 18/20 combo:
I really like this (you can see the deep lip or the rears):
here's my photoshop of that last pic (lowered front):