I am currently running Kumho Excsta LX Platinum at stock size 225/50 and 245/45 with OEM 18" Sport Rims (18x7.5" F and 18x8.5" R) and 15mm spacer in the front, 20mm spacer in the rear. I have a moderate drop as well, tire height is flush with fender, maybe the slightest tuck in the rear.

The title basically says it all. With my current drop, and 15/20mm wheel spacers, would I be able to fit 235/45 and 255/40 Bridgestone Potenza RE760Sport without any rubbing issues? OR, Hankook Ventus V12 235/40 and 255/35? Pic added to show gap between fender and tire in the rear.

Any suggestions?