Define a bit of weight? Most cars don't need aftermarket transmission coolers as the transmission system was designed to hold extra weight a transmission only really becomes hot with constant gear changing if your going to be driving in areas that are up and down hill a lot then you may consider one but if it's going to be pretty much highway driving and flat roads I wouldn't bother with one and even if you do come to a long hill it's best to do manual gear changes locking it back through the gears so it doesn't change up and down as your climbing also when towing have your transmission in power mode.