But both R32 and S3 brakes fit under 17's? (As you can tell the key here is finding cheap (ish) brakes I can fit under 17's
I hope these are not to go on your monster TT.
The R32/S3 set up is a good upgrade over standard, but i dont think they would be sufficient with your horse power unless you are fitting a parachute as well.
I had B5 RS4 front brakes under my 17in track wheels. These had 360mil discs but just scraped under.