The stock wheel width is 7.5" up front, so you're not really upgrading much, if at all. Ideally 8.5" would be a minimum front width combined with a 9.5" rear - I never recommend more than a 1" difference in width between staggered wheels front to rear as anything more will likely hinder performance. I did feel like 18x8 was great in the front with the 350z reays v1 combined with the 18x8.5 rear, so you might be fine. But the handling wouldn't be optimal compared to what it could be with better specs in your case.