Goal of my upgrades was to have a better "stock" look, not void my factory warranty (still some risk), and actually have a truck that could go down a fairly rocky dirt road such as in a National Park. Stock truck rode perfectly on pavement but off-road bounced so much that it felt like the truck was ripping itself, and me, apart at just 20 mph. What I ended up doing is like what GM is now doing with their "Trail Boss" package (package has 2" lift, 33" tires, Off-road struts/shocks, skid plate, Eaton locker rear end--I think). This forum was key to helping me and I want to give back and hope it helps others in any possible way. Other site I used was "CustomOffsets.com" gallery--I tried posting these photos there recently but they no longer allow "stocker" truck postings.
Summary: Bilstein 5100s front (highest setting) and rear. Stock rear blocks. Toyo MT Load Range "E" model (exactly 33 x 12.7 per Toyo site). Stock GMC rims (18 x 8.5; +24mm offset; NO spacers).
Bilsteins: I got 1.5 inch lift in the front (others are reporting getting more than that). It would look better to me with another 3/4" but I got what I got and don't want to add anything other than the Bilsteins due to my GM warranty concerns. Bilsteins eliminate the body roll in turns, take bigger dips great, and have cut my dirt road driving bounce in half versus stock--they ride fine on highways at speed also. Given the Toyo MTs have such deep tread and have some "tire squirm" in higher speed turns (ex: highway entrance ramp), the elimination of body roll with Bilsteins is very helpful to keep the truck "planted" so it doesn't feel like it will get away from you. I also think the Bilsteins are better for the suspension because the Toyo MTs weigh twice as much as the stock tires and the Bilsteins handle that weight better.
Toyo MTs: I have not had any rub except for on the liner on the passenger side and it was only at full lock--one zip tie fixed that. I have at least 1/2 inch clearance on sway bar and upper control arms in all directions at full lock and with the suspension "articulated" as in an off-road situation. For you tire shoppers, I did NOT have to do any NorCal mod and do NOT have any rubbing, but if the tire diameter was any greater than 33", I would have had one point of contact on the driver side at full lock with suspension articulated--again, I have no rubbing with what I bought. Each of these trucks seem to have slight build variations. Some folks report using greater diameter tires but my truck would have an issue with any bigger diameter tire. It is critical to look at the exact tire specs for each tire considered on the respective manufacturers website as well--one might be labeled 33 x 12.5 but only be 12" wide. For looks, I wanted a "wide" tire also along with that aggressive and functional tread design (I do not tow and am never in snow) and sidewall puncture resistance. Never had off-road tires before and was surprised at how fine the Toyo MT rides, even at 80 mph (I am a lifetime Michelin LTX guy before this as comparison). Tires have triple ply sidewalls and the tread is beautiful but it does burn off quicker than you would like it to--you gotta pay to play.