+1 for the suspension maxx stuff above.
'07 Denali Yukon XL 200+k w/blown auto ride (Z55)
Goal was to add little more ground clearance and level it off while still being able to tow my boat.
I started with the Arnott replacement kit: new front struts (loaded with new springs), air ride rear shocks and new air compressor. FWIW; This was night and day compared to the blown struts and shocks when I got it. Handled fairly well for a large beast, including towing a boat ~5k.
I still wanted to get it leveled off so I used the adjustable front kit mentioned above - you can only go 2" max due to interference/bind with the "stock" upper control arms. The kit includes a multi-holed bracket to relocate the height indicator sensor for the air ride system based on how much lift is added to the front.
It was now leveled out but it still sagged a bit in the rear when towing the boat (saggy rear springs). So a few months later I added the suspension maxx 1.5" rear spring blocks and heavy duty Moog replacement rear springs - they are listed to be 3/4" longer their stock replacement.
When I did the rear, I also picked up a set of tubular upper control arms.
1) I needed to replace the stock ones anyways - bad ball joints
2) To be able to add the addition .5" lift plates to the front, I needed a ball joint/arm that provided more articulation.
3) I found a deal I couldn't pass up on a set of Icon tubular upper a-arms.
It sits level with a little more ground clearance now and I should be able to fit a set of 33s without issue but haven't done it yet. Waiting for the current tires to need replacement and trying to decide what wheels I want. I think I could go up to a 34" tire but I don't want to mess with gearing right now.