Rocks hit them more when they are in front of a radiator. My converter is 4200 stall. I beat my car on the street and soon at the track. Two coolers maybe overkill but not ever having to worry about cooking a trans is just enough. Seems pretty self explanitary to me. I want a clean clutter free car and this helped. That and now I don't have a trans cooler in front of the radiator limiting my cooling capacity.