I also use the Carbotech XP10/XP8 combo on the track based on a recommendation by the Carbotech guys. They slow the car down and don't fade - that's good enough for me. I chose Carbotech because I can switch to their street pads without changing rotors.
It's been so long since I have used street pads on the track that I can't really compare the feel. Maybe a little better initial bite, or maybe I have feet of stone and it doesn't matter.
Edit to add: I also have the Quantum Motorsports brake cooling ducts on the front. Not that I had any fade, even with my American Iron instructor driving the car, but hopefully to keep the pads a little cooler and reduce wear.
-Wayne