Reviews of AP RACING brake caliper

I run 9660 on my m3, very satisfied on street and track, did consecutive hot laps and did not show any signs of brake fade, and constant strong initial bite. I like how I can modulate the braking power through these AP 9660.

When I was converting my E46 M3 to a race car, I looked at AP Racing products. At the time, they had two kits for the E46 M3: a street kit with a fancy looking four pot caliper and 355mm rotors, and a race kit with super dull looking 4 pot caliper and 325mm rotors. That's 7mm *smaller* than stock. I went with the race kit. I generally do 25-45 minute sprint races with the car and I've never had even a hint of fade.

Personally I would not delete the proportioning valve. I run 304x25mm front with AP Racing calipers and stock MKIII rear disks with MKIV calipers. The stock MKIII proportioning valve can be adjusted to the point there is too much rear bias.