Travis, I tow with my ST all the time. I have towed my old Show Truck (1987 GMC Sonoma) on a heavy uhaul car trailer over the Pa., W.V., Oh., N.Y., Conn., R.I. mountains and didn't have much trouble, I was in the higher RPM ranges most of the time but I was also climbing some pretty big mountains. I tow my custom made '98 S-10 back-half trailer loaded down with upto 3,600lbs. (the trailer is 1,000lbs. empty). I also tow my neighbors utility trailer with just about anything you can haul on it.
Keep in mind I have a class IV htich, not using the bumper hitch.
When I towed my GMC with my Trac in stock form it did o.k., I think it handled better after I lifted it and went to the 33's, JMO.
For the gears I'd email either Chad or Todd Z, I know Chad had 4.56's in his IFS diff before he did his SAS and I believe Todd has 4.56's in his Green Trac.
You may want to look at Todd Z's trans cooler too if you tow long distance, maybe look into a remote auxilary trans filter too.
