I ahd a 2001 suburban with the 8.1 liter and towed a 35' Cedar Creek camper. I loved it!! The AutoRide function helped significantly. I think it tows better than my cummins. I could pull Black Mountain at a steady 55mph!! it was very very strong bone stock and not too bad on gas.
I highly reccomend the suburban 8.1 liter to anyone.
I drove my dad's Dmax and pulled the same camper and couldn't feel a difference.