I have had many RX-7s and still have 3. The rotary engine is great. They can rev much higher than "pist-on" engines
. They have a buzzer, but not a rev limiter, so if you go 1k RPM over redline on stock internals, bye bye engine (not that its happened to me).
Some helicopters and small airplanes use rotary engines, in operation they will be running in the 4.5k-6k range, in time of flight.