Install leveling kit
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&vxp=mtr&item=271086413411
I bought this for my 2012 Z71 tahoe. Installed it myself in a parking lot and did not have to unbolt anything except the shock/strut on the bottom. Slid the blocks underneath and bolted it back. The key to this is using a bar that is atleast 3' long to pry the coilover up 2" when you slide the blocks under. Really simple and cheap way to lift your truck. I got 2.5" out of this and it rides the same and all my CV joints are still aligned perfect.
Keep in mind the old Z71 tahoes had torsion bars and replacing the keys on them really messed with the angles of the CV axle and the ride quality. But this keeps everything perfect.
I attached a picture of my truck so you can see what you have to do.