I don't know much about the PFC, but from what it looks like (it replaces the factory ecu) then it sounds like the Cobb unit may be our final answer for tuning. It has the ability to reflash the 8's stock ecu and change many important parameters. It is supposed to be available Spring 2007.

 

They do have the Racing Beat PCM flash, but like people are saying here it is nearly impossible to have the massive gains that you saw on an FI-ed car vs. an NA car like the RX8. Turbo kits like the PTP/Mazsport/Pettit/AFSC are all coming out.