There are a lot of rumor mills suggesting the engines are unreliable, not the truth.
The RX7 has a twin rottary setup which takes its capacity to 1.3litres. This is capable of producing a massive 500bhp at the rear wheels in NA form. You can litterally bolt another rotor on if you wish with a crank to suit. They respond very well to turbo charging and can go stupidly fast, 230mph+.
Aye, no reciprocating parts so can rev really high.
Effective capacity is twice the quoted capacity because every volume does a comple cycle for one crank revolution whereas on a conventional engine they only do 1/2 a cycle.