The most important thing about the tires is their measured diameter. Anything more than about 32" is going to catch on the bodymount near the firewall on the chassis under moderate turning/full compression. No amount of lift will avoid this.

Having said that, most manufacturers are "optimistic" about their tire sizes, a "33" may in fact measure 31 inches when mounted.

12.5" wide may be an issue with clearance to the firewall near the "A" pillarduring turns. The last thing you want to do is to crush the "A" pillar with your BFH as this would seriously compromise the strength of the body, possibly leading to windscreen fractures, further spot-welded seam movements/seperations, and other assorted issues (door drops, squeaks/rattles as the body shakes itself to bits)

Lesson: Take a tape measure with you when buying tires