It's more myth that rotor motors need to be rebuilt everytime you gun it. The Series 6 RX7 is a very well engineered car. This myth mainly comes from the older series 4 and 5 turbo 13B's.
I looked at them when I was looking for my car (Not import, Mazda delivered). The main problem is trying to find one in good nick. They also have a problem with the turbo's, something cracking. Read that somewhere.
But being fair, I'd take the RX7 if I was after a track car cause they handle very well, and in my opinion, better brakes (even though it's the same calipers) than the 32 GTR. Probably to do with the weight. But for an everyday car, the R34.