tow vehicle upgrades

I think you got some good info here. Definitely a WDH and a Sway Control. If your rig has a trailer towing package, I doubt if you even need a auxiliary trans cooler. I have a 1999 Suburban with a 5.7(350cid) that we used for many years pulling a comparable size trailer(25' bunkhouse). I hear the 5.3 is quite a bit more powerful than the 5.7. I always wanted to do the Banks Power Pack, but never did. I wouldn't put any performance kit or parts on unless it was from Banks. They have an entirely engineered package. My Suburban came with the factory tow package that included the auxiliary cooling(including a remote trans cooler). I never did a thing to it and we pulled that trailer everywhere at any temp and never had a single overheating issue. If I was going up and over some giant mountain like the Guadalupe Mountain Range out of Texas into New Mexico, I would put it in 4 wheel low to take stress of the transmission. And we had it serviced quite regularly. We finally replaced the transmission @ 319,000 miles, only cause my wife was getting concerned that we were getting ready to go on a long trip and there is very little in the way of repair shops on Hwy 395. It actually still worked perfectly. You really should be fine stock. If you don't think so after towing, then revisit the subject.