Stock shocks are fine, no need to change. 285's fit on stock wheels, or aftermarket with stock offset - mine were positive offset, stuck out almost 1 1/2", had to trim the rear of the front fender, and clearance the bumper and valance so they wouldn't rub during compression. I had mine cranked about an inch or so, stupidly cranked them to the max to clear everything - replaced my BJ's and pitman and idler arms 3 times in 4 years before I wised up.
When I did my rears, I used leaves from a Suburban, and slipped a leaf in between each stock leaf.... Cut each one on a metal chop saw so the length of each leaf was shorter than the leaf above it in the pack, NOBODY would know that it wasn't stock unless they were another TYF forum member (not even the techs @ the garage I take it to knew). In addition, swapping in extra leaves also adds to the load carrying capacity... I also swapped in beefier leaf spring hanger brackets when mine started to crack.
Just an FYI... I carried 40 pieces of 12" wide x 17' long rough cut strapped to the top, and I wasn't even close to bottoming out. Each one weighed well over 40lbs, probably closer to 50lbs. Previously carried 24 sheets of 1/2" plywood, 18 2x6x12's, 5 rolls of torch-down roofing, and 3 rolls of roofing felt, without bottoming out. Also towed a 9000lb Komatsu backhoe on a 20' trailer, no worries about swaying while towing @ 40mph....
