ok, their gas milage is horrid. No matter what. Remember that. And it only gets worse with more performance mods. Naturally aspirated (non turbo) RX-7's like mine are actually pretty reliable, but they dont have too much power. 110k no engine problems yet. The problem starts when you start supercharging them. And third gen's are all twin turbo. Third gen's engine's pop easy, because people put crazy boost on stock parts. Even stock, third gens go at about 100-120k. And they aren't cheap to maintain.
Not to scare you, but i want you to know what you;re getting into before you buy one and end up hating it.
Anymore questions?
*edit* if you really want all the nitty-gritty, go to rx7club.com and look through the threads there.