You're always welcome to run E Production in the RX-8. I believe the T4 RX-8 is completely ITR legal, so if you put "ITR" stickers on the side of the car, you can run in EP as an ITR car without changing your brakes or being hit with the STL rotary tax of a massive restrictor. If you then want to try slicks, pull the ABS fuse and run as a full-fledge EP car (with the exception of ABS, your T4 car should be 100% EP legal). The RX-8 has also proven to have a lot of potential in EP, too, with one finishing in the top 5 a couple of times at the Runoffs.