We sold our tow vehicle. We have a 2013 Premier 32bh and our 2005 Chevy Silverado 1500 just wasn't quite cutting the mustard. It towed just fine as long as the road was flat. We decided that we bet...
I'm a Chevy guy, my upgrade was from a '04 Chevy 1500 5.3 3.73 to '07.5 LMM Duramax. Towing with diesel is such a nicer experience vs a gasser in my experience. Also, having a 6 Speed is much better than my previous 4 speed transmissions.
If you don't mind the Chevy's classic body style I'ld look for Duramax with the LBZ, less emissions requirements and better towing fuel economy. That said I wanted the newer style so I got the LMM engine. Very pleased with the truck.