The rotary engine in the RX-3 was the 10A in most markets, but in the United States the 12A from the RX-2 was used. It was a longer engine with greater horsepower output.
All of these cars had the engine mounted in the front and rear wheel drive. They were very good performers, claiming many victories in racing circuits like the Japanese Grand Prix.
The RX-3 did not perform as well as its predecessor, the RX-2, on many racing circuits because its engine weighed it down. The RX-2 was usually raced with a smaller engine than the U.S. consumer model had.
In 1972, the RX-3 became the first station wagon to have a rotary engine.
On a unique footnote, the Aero Design DG-1 racing airplane utilized two of the same engines used in the RX-3. They were mounted in the front and rear of the aircraft.
These cars are hard to find on the used car market. My suggestion is to look on eBay, where they are usually cheaper than private sellers anyway. You might also find some very rare parts on there.