Yeah, that would be pushing it according to this thread. https://www.crossfireforum.org/forum...-18-front.html

But the 255/35-18 is the same diameter as the 225/40-18. The rims in that thread are 9" wide with a 30mm ET vs a 8.5" wide rim with a 32 ET

This says they would be just under 10mm closer on the inside
Online Wheel and Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit

Do you have the Koni Shocks installed? Mine had them installed when I bought the car. They're set as soft as they will go and although they take some of the harshness out you still can feel the bumps. About a week ago I bought three 40 lbs bags of water softener salt and put them in the hatch area. That extra 120 lbs plus the spare tire weight (30 lbs?) made it ride super smooth. So for daily driving try driving with some weight back there.