I use the slotted two-piece front rotors by Racing Brake. Nice quality and save around 10 lbs of weight.
Performance Brake Parts, Rotors, Calipers, Discs & more! - RacingBrake.com
I then matched them with the Stoptech slotted rear rotors.
So far it's seems to be a good system but haven't had a chance to see how they perform on the track.
Just trying to give people some other viable options.