Dunno how relevant this is but when lotus built the esprit they used the same gearbox ive got in my 5 (renault un1 transaxle) and when they put a full undertray under the gearbox it overheated the box, so they had to run without, and that was on a road car.
So i would say having a cooler on a track car is a good thing.
Id like to do that to mine to.