If you want to know about RX-7s join up at www.nopistons.com. Some of the guys there really know their stuff. Useful links as well.
Like Rev210 said mainly you just have to warm them up correctly and make sure you change the oil frequently, more often than a piston motor.
The FD models are the least reliable of them all though. They are prone to vacuum leaks because of the complex sequential twin turbo system and sensitive to overheating, again because of the twin turbos; the manifold is very short, and there isn't a lot of underhood space, so there is a lot of thermal stress on the motor.
J