Sold my 255 17" tire setup. Purchased
Titan7 18x9.5 wheels
Falken RT660 275/35r18 tires
The tires rubbed, a lot.
Grabbed a fender roller, heat gun, pulled out the fender as much as I dared.
Still rubbed. Found the worse locations were actually where the rear bumper meets the fender, and at the back of the front fender-well. not the fender itself, but there is a frame rail behind the plastic liner.

I didnt take any photos of hammering the frame-rail protrusion down, but SpeedAcademy did a brief video on it on an episode with a FRS. 3 minutes 20 seconds in the video... screenshot here:
after that I have no rub in the front other than extremely tight turning radiuses, which i expected and plan to limit my steering input.
To combat the rear rub, I purchase RacerX adjustable upper control arms.
With these I pulled the wheel inward just a few millimeters using the upper arms and balanced the camber adjustment on the lower arms.