I have an air tranny cooler- it is off a ford exploder. if you are keeping the stock cooler as well, plumb in the air unit from the drivers side of the radiator, as that is the flow back to the transmission.

I installed mine because of leaks, and it is the only cooler I run.

on the hitch- I have posted many times on this issue, so a search w/ my name may be helpful. I have towed heavy, (beyond rated capacity- Shhh...) and not had any issues. I routinely roll with close to 1K IN my car, and while it does slow it down, I make sure that my brakes and mechanicals are in top shape.

the curt TD hitch fits right on a sedan, but the muffler tailpipe needs to be modded.