I got the inside scoop on this from a buddy of mine that drives an RX8. Apparently the problems were caused by software that didn't open up some kind of oil venting valve system properly. The resultant backup of oil caused a seal to fail and let excessive amounts of oil into the intake/exhaust flow, which fouled the catalytic converter. If the problem is caught early enough and the software is updated then everything is fine, but if its not caught in time the owner gets a new engine. From what he's telling me it looks lime Mazda is going to replace the engine every RX8 made since 2004.

Man, that's gonna be expensive...