Common performance modification for the RENESIS 13B-MSP rotary engine used in the Mazda RX-8 include modifications to the Engine Control Unit software, adding upgraded air intake and exhaust systems, and adding a forced induction system such as a turbocharger or supercharger. Due to the unique nature of the RX-8 engine's design, many conventional engine modifications, such as increasing displacement via reboring the engine's cylinders, are not possible on the RX-8 engine.
Improving an engine's power by increasing the maximum airflow to the engine and optimizing the flow exhaust out of the engine are common modifications for any combustion engine. In the case of the RX-8, Mazda's performance engineering division MAZDASPEED produces upgraded air intakes intended for the RX-8 that can increase power output, while most exhaust modifications are produced by aftermarket companies. Remapping an engine's ECU via software to improve performance is also a common modification for many engines, though modifying the RX-8's engine in this way tends to produce less power gain than for other engines.
Adding forced-induction systems such as turbochargers or superchargers is the primary way for tuners to produce large power gains from the RX-8's engine. These gains can be as high as 150 horsepower or more over the stock engine output. Pettit Racing produced a "bolt-on" supercharger kit for the RX-8 in the United Kingdom, but availability of this modification may be limited as of 2015.