If you want to fit 255 under your fenders without doing serious work, offset is KEY! +48 is about ideal. I run 17x8.5" +48 with 255/40/17 and I'm just a couple mm from the strut and I still have slight rubbing on bumps on the rear fender lip. You can do +42 if you want, you'll just have 6mm more fender work to do. Camber helps but that requires special parts to get a decent amount.
There are 17x8.5" +48 5x100 choices out there, you just got to dig.