I have the Cornfed 3/2 with 285/70/17 tires on my Runner.
You will need to trim the inner fender well lining and molding closest to the firewall as well as either trim or push the lining in at the front.
Remove the mudflaps as well - no chance in running them.
I didn't make any modifications for the rear and don't have any issues.
I'm running 1.5" spacers also and that's what I had to do. When turning sharp, I still get a bit of rub on the plastic, but don't really care anymore...:lmao:
Hope that helps.