I know there are lots of guys having trouble with the ifs, but here in Norway and on iceland there are LOTS of ifs trucks with 33s and upwards without any (eh, with only slightly) trouble. It all comes back to your driving, know your car and its weaknesses and its my oppinion that it should last. But a sas kit is on my wish list, I just have to get it pre-approved first...
Toyota in Norway give cars with ifs and 37s full waranty!!!!!!
and I have run it on 35s and 37s for 18 months without any trouble...