I'm getting the ZO6 rims for my formula and have a 99 z28 rear in, what other mods do i need to do to make the wheels fit? Can i use the eibach springs or will that be too close?

I would also like to know cause I am gonna be running 17x9.5 upfront and 18x10.5 in the back..

I have 18x9.5 rims on all four, with 10.7" of tire dropped 2" on all four, too - I have NO issues in the rear, and only have minor rubbing issues up front if I'm not responsible (speed bumps/potholes/dips too fast). My rims are +56mm offset and am using 2" adapters all around. Hope that helps

So then other then spacers the wheel wells should be fine?

It depends on the backspacing and offset of your wheels.

i had originally planned on getting some 17x11 zr1 rims but after talking about it on some threads i decided it might be too wide and effect the ride quality. now im considering 18x10.5 c5 rims. i plan on a fourth gen rear once i find out where i can get a good ecable. so ill only need spacers up front. i dont mind getting the fender lip rolled or banging the wheel wells a little bit (as long as its something simple i can do myself). but i would like to hear from somebody who is running 18x10.5's in the rear. what mods were done? lowered? hows the ride?