You should join the rx8club and do some reading there.
From what I've been able to gather on various forums, RX-8s were hit and miss as far as engine problems go. I know Mazda has replaced quite a few engines in them. Apex seals seem to be the achilles heel, some having problems early and some seemingly last forever. Use of synthetic oil was named as the cause of some failures, and synthetic is recognized as a no-no for the rotary now.
Oil consumption seems to have been an issue with some owners who were unaware that the engine is designed to consume oil. There's actually a dedicated system to divert oil for this purpose, so some unknowing owners ran their cars dry. Oil level must be checked and often topped up periodically.
The most frequent gripe I've heard is the lack of torque. The engine is small and while it produces upward of 200hp, torque is down around the 130s so straight-line acceleration is less than stellar. Where the car makes up for the lack of muscle is when the road turns twisty. Track times remain good for the car due more to agility than raw power.
I read something a while back that I remain skeptical on....the statement that the car should be warmed up extensively before driven. I haven't seen anything conclusive on this. It's also been said that it's actually better for this engine to rev the crap out of it rather than putter around. I just didn't get a clear picture about why this is...I suspect carbon buildup in relation to optimum operating temperatures. For these reasons, some people on various Mazda forums have found it to be a less-than-ideal daily driver or commuter car.
Considering the potential for problems, speaking for myself I'd pass on an RX-8 with that many miles on it. But I'd pass on almost any car with that many miles on it, so that doesn't speak for an RX-8 specifically. The older I get, the more I despise car headaches.
Happy hunting!
