A good tune running 93 octane does make a huge difference with the GM gassers. But if you do plan on towing quite often looking at the diesels should be suggested.
I towed a lot with my 1500 Silverado even after putting a 6.0 in it with heads, cam and a turbo it pulled heavy loads great. But your never going to be as efficient as a diesel. But then again diesels are expensive and costly to service.