Most people don't touch the rear end when they put on 285's. The rear sits in the sky anyways. You need like 2.5 inches of lift to make the truck sit level. It would look stupid if you had the front sitting lower with glass fenders. It needs to sit at least level.
It depends on how high you lift the front with the coil overs. You can go any where fron 1.5" to 3" easily. If you go the 3" route then a rear aal or 1.5" block is in order. I have hoes on the front of my 06 dc and started out with 3" of front lift and rear aal. The ride was real stiff, so I took the rear aal out and dropped the front down to 1.5" and the truck sits level. I hve the sport and used the stock wheels(chromed) with 270/70/17 Revos and i measure 7 1/4" from top to tire to fender well an all four corners, and the ride is nice.:thumbup:
well I lifted the front of mine 2.5 inches and I had to trim the rear part of the fender flare a decent amount, but 285's fit with american racing mojaves which are a 4.5 inch backspacing. With the 2.5 inch lift my truck sits like 1/4 inch higher in the front.