I was able to strengthen and straighten out the rear corner panels pretty well without replacing them, but it was still a lot of work (see http://www.airforums.com/forums/f36/...ml#post1172246
I think that you will gain some ground clearance by going to 225-75R16 LT tires (maybe 3/4"). But if your axles are saging, I think that you'll gain a lot more ground clearance by going to 32 degree down axles of a slightly higher rating. I'm planning to do both this spring (although I dread the expense). I need new tires because of age and I don't plan to stick with ST tires after all of the problems that they've caused in the last few years. That forces me to go to 16" wheels too. My axles are saging and tired so they need to be replaced anyweay.