I tow my 31BHPR with my 1/2 ton Denali with 383 hp and 6-speed transmission. I had no problems keeping up with traffic or with trailer sway going over the Rockies or in high-crosswinds.
We were on the road for 27 days towing the Premier--we love it and we've put it through a lot. At the very end of our Vancouver to Minneapolis road trip last summer, we suffered blown-out bearings on one wheel caused by a bent axle. We covered thousands of miles, went through dozens of construction zones, and I drive with a heavy foot so I don't know the exact cause or time of the bent axle (shhh, I also backed up over a curb). An unevenly worn tire that I discovered after Minneapolis should have signaled a problem to me. In the end we spent an extra 3 days in Deer Lodge, Montana (not a bad thing, actually) while we waited for a new axle.
Our Denali is still going strong despite all the abuse I give it. That being said, my future plans are to get a 3/4 ton Suburban or 1 ton van to increase our cargo capacity--but I sure will miss the Denali's power!