Mazda is a very, VERY good customer, so I have a hard time saying this, but stay away from an RX8. They make me a lot of money, because I manufacture the plastic shipping containers they use to ship the RX8 engines back and forth to reman, and they buy ALOT of them.
The platform is an excellent car, except it's kind of uncomfortable for the passenger, hence I now own a CX7 for my DD, instead of the 04 RX8 it replaced.
They have considerable issues with the rotary engine because they are trying their best to keep it alive in today's market and that won't happen much longer. They are running it much leaner than it wants to be run in order to keep emmissions down. The rotary is a two stroke that is exhausting gas before it has completely burned. They get horrific gas mileage, I'm talking friggin terrible. You could hot rod the hell out of a boxster or S2000 and get better fuel consumption than babying an RX8. My 04 was down to under 15 mpg communitng on the open interstate.
All this said, Boxster owners with rear main seal issues and other catostrophic failures could only pray Porsche would take care of them the way Mazda has done RX8 customers.
If Mazda figures out a compact piston engine to keep the RX8 platform as is, I'd buy another in a flash. I really did love driving the RX8 and it was the roomiest, practical sportscar ever.
On to S2's. Too cramped inside. I love the cocoon feel in my Formula car, but it gets old fast in a street car.