I used a B&M cooler kit, had to get some extra hose and an adapter fitting. Also Depending on your millage you may want to go ahead a do a trans flush. You would be surprised how poorly the fluid looked on the one we installed with 27k on it. This is the cooler I used.
http://www.bmracing.com/products/702...-rating-black/
So far seems to be working well, I will report back after tuning as the car is currently only on spring pressure.