This may be useful to you:
http://www.rx8club.com/showthread.php?t=116484 - not really on subject but here is a nice list of problems and their fixes
http://www.rx8club.com/showthread.php?t=219328I wouldn't call them high maintenance. Most people don't take care of their cars, that's a fact. Most people don't even know what they should be doing to maintain their cars. This is also the case with many owners of RX8s; I believe that there has somehow been some stigma about reliability because so many people just don't maintain the cars, like, you know, changing the oil frequently. The history of the less reliable RX7s doesn't help.
I've got 44k miles on my 2010 and I've only changed fluids and plugs/wires. When you change the oil in these cars you only change half of it (about 4 quarts out of 7 and change), so the frequency at which you change the oil is important. Find out how frequently the owner changes the oil in their car. I'd ask them how often they have to add oil to the car, usually it's about a quart every 1.5k miles or so since it naturally burns a little oil. Carbon build up can be a problem in these cars if they aren't allowed to rev high once in a while; cars that are high mileage and have been driven around at low RPM for a long time likely need to be cleaned out with some sort of decarbonizer and may not run well at high RPM. Running shitty gas with less than stellar detergents doesn't help. Ask him if he ever runs it up to the redline. It's clear to me that oil and carbon buildup issues are likely the main cause to many people's "rx8 woes". There is a reason why the series 2 RX8 has 3 oil injectors per rotor housing rather than 2 in the series 1 cars.
I've heard of people flooding their motor, but if you let the car warm up before shutting it off, it won't happen. The renesis motor runs very, very rich after a cold start and becomes leaner as it heats up. They really aren't efficient at all until they are hot. Newer cars have stronger starters to try to combat flooding, but I've never known anyone to have these problems, only read about them.
Also, nothing you do will change the gas mileage on these cars and after market intakes are completely useless and sometimes hinder performance.
My advice is to change the oil often as you can (Mazda recommends 2.5k miles), check the oil level every couple fill ups and keep a quart in the trunk. Rev it high once ever few days, but only once the car has completely warmed up - that includes the tranny, not just the engine water temp. The eccentric shaft is what rotates at 9k RPM, not the rotors. Look to replace plugs every 30k or so.
This used to be a great place to look at TSBs and recalls, but the main link doesnt work anymore and redirects to a dealer page. Still has some useful info imo.
http://www.rx8club.com/showthread.php?t=14453