The custom tow tune is better for towing than the canned tune. In my case it had a noticeably more grunt (also gets better mileage). The 87 custom tune will probably be equal to or just slightly better than the 93 canned performance...all the while staying on lower quality gas.
As for upgrading, you should be good.
http://forum.gopowerhungry.com/upgra...-upgrades.html