I forgot to add the specs; these are 33's (33.1" according to manufacturer) LT285/75/R16 - D load range, 3-ply sidewalls. I wanted Hummer recommended/stock size to stay within factory specs for now; maybe at some point later I'll upgrade to 35's, but I was concerned about street performance with 35" set since I drive the truck daily around the town. I practically feel like having a new vehicle after I got rid of the 20" set and removed low-hanging chrome nerf bars - huge improvement in the side's clearance - not worried when climbing over terrain now. I may install the OEM rocker bars for protection.
Tires seem quiet on the road (I expected worse), only when turning the noise sometimes increases a bit, I guess the rough sides make more contact with the pavement that way. Dealer inflated them to 35psi and that's where I left them for now. I think I can air down significantly if needed (once I get onboard compressor). These ProComps are also supposed to be very resistant to punctures - very important to me because the terrain we have here.. finally - ProComps are Made in U.S.A.
here is the manufacturer link:
http://www.procomptires.com/xtrememudterrain.html