I have been using Carbotech's for 2 years now and have been very pleased with them. I used to run Hawk Blue. Even though I dont run an RX-7, I have had great luck with them on my Honda. The pedal feel is always consistant and the pads are very easy on rotors. The pedal is always predictable with great modulation capability. I would recommend the XP8. The XP12 might be overkill. All the pad compounds are listed on the Carbotech website.
www.ctbrakes.com

Good luck.