I have a 2010 T&C Touring w/NO tow package. What after-market upgrades are suggested to approximate the manuf. towing package?

I tow infrequently: 4 times/yr with 4x8 trailer for yard soil, furniture buys, camping. However, I'll be picking up a small camping trailer and would like to tow up to 2800lbs and the vehicle be passenger loaded. Realistically, towing only 3 times/year on mostly flat terrain for at most 200 miles one-way in summer weather (no crazy winds or storms).

Towing Basics: Class III hitch w/2" receiver & 4/7 pin wiring harness, ball mount, riser.
Trailer Upgrades: Brake controller & weight distribution bars. Anti-sway kit??

The BIG question: Vehicle Upgrades. Which get the most bang for the buck?
* 2010 T&C Rear Suspension Enhancement example @ etrailer
* 2010 T&C Transmission Cooler examples @ etrailer
* Engine Oil cooler, is upgrading existing radiator possible?
* Brake upgrades possible or needed?

I don't know how these or other options compare to the real upgraded T&C Tow Packages. I need guidance on how much to upgrade the vehicle given the little amount of towing will be done, albeit not a light garden trailer anymore.