If your engine is stock I don't see a need to install a cooling system of your transmission. I didn't hear from somebody that the seat's gearbox can be overheated. I know cases when it was overheating but the engine was stage 3 and of course, it's very high pressure on the gearbox. I added a transmission cooler on the gearbox of my Golf 7 R that is 450hp)) In this case, of course, the cooler is indispensable. I installed it and I felt the result from the first ride and it deserves the money that I spent.