I've used a few caliper rebuild kits over the years on my track only 996 GT3 and over 6k track miles, Centric, OEM Brembo and RacingBrake and the best so far has been RacingBrake. They cost a little more but the quality is top notch and for track use where you want and need brakes i figured it was always worth the extra for no hassle braking. Their stainless pistons also look the business when installed.
Success! My suspicion that one or more caliper pistons were dragging/not pulling back seems to be true. Ever since the rebuild (rebuild kit from racingbrake dot com), braking performance is exceptional. Better than it has ever been to be honest. Not sure how long my braking system has been compromised since it likely got worse (gradually) over time. It got it be point where pads would overheat after a couple of hard stops. After that, I would have to stand on the pedal to get any decent braking force. Until now I’ve tried bleeding the system and changing out brake pads to no success. I was leaning towards the CCM rotors needing to be replaced ($$$). So glad I gave a full caliper rebuild rebuild a try before making that sizable investment only to find out the problem persisted.
Not only is braking performance better than ever, the car rolls into corners more freely (brake drag gone) and the chassis balance during trail braking has been restored. Very very happy. Whole job took 2 evenings working slowly. Total parts cost for rebuilding all 4 calipers (with upgrades high temp seals and vented pistons) was around $1200. I’m in now way affiliated with racingbrake. Just a happy customer.