I'm joining this thread because I'm considering the Tru-Cool Max (which is rated at 40,000 pounds of gross vehicle weight...overkill by about seven times). It was developed for situations where the cooler in the radiator is contaminated, or for heavy duty diesel applications. It runs over $100 (but is 2x as much cooling as others that cost half as much), but it is cheap insurance IMO. It has a thermal bypass valve which lets fluid bypass the cooler until it reaches operating temperature. I'm planning on running synthetic fluid, so overcooling won't be a big issue for me, but it could help in cold climates for people running petroleum based fluids.
I was thinking that if a target temperature for the fluid is about 130*F, why risk heating it up by having it go through the radiator (thermostat setting of 195*F)? I was also thinking that keeping the transmission fluid out of the radiator eliminates the potential for cross-contamination and won't kill the tranny if the radiator ever blows out and overheats.
I haven't done this yet, but I'm interested in other's experiences.