on a stock radiator with electric fans. That mechanical fan is a power hogging beast, but g'damn it moves a TON of air. I have heard people who have attempted an electric fan conversion on the TT's and they had heat problems because of it. However, I recently met a guy who put a Howe radiator in and used some aluminum sheet (like 1/8" thick) and made a fan shroud for it and used one 16" (or somewhere around there) electric fan. He runs low 12's with that car and says it has never overheated with that setup.