hi again Lee!
I went from 235's to 31"s this year (with 2.5" susp & 2" bodylifts already done) and they fill the arches great, but...
yeah, they'll rub; bottom rear inner corner of front wheel-well, possibly also the lower lip of front bumper ( no big deal) and the chassis on turning; and probably ther outer rear lower edge of the front arch on articulation.
the rears also will rub on the lower front outer edge of the rear arch on articulation.
Iv'e had the outer arches radiused by about 2" at these points, up to the fold in the bodyline, and the inner corners of the front wheel-well's cut back - no need to push back the floor pan!
I was keen to refit the plastic guards, so ensured a proper lip was formed where the arch was radiused. I was able to refix the plastic with new clips to 2/3rds, and with carefully drilled & screwed self tappers elsewhere, cutting off any surplus plastic where it was out of shape due to the new curvature of the arch.
It keeps out the worst of the mud, preventing it from getting up to the top of the wings, but don't try and make it water tight - you might want to squeeze the jet wash in behind one day if traversing deep muddy ponds!
I have the rubber spats fitted, so covering the damage wasn't so bad, and these mods have been sufficient for the greenlaning I do.