For those who want a little more than stage 1, we have a stage 2 which consists of optimising a number of elements around the engine to increase the efficiency of the engine. Primarily this is about intake and exhaust. A lot of air-intake systems are very restrictive because of their anti-resonant structure which is intended to damp the intake noise of the engine. By mounting a sports air filter or custom air intake, more airflow to the engine is allowed and we get a nice power gain. As we reach the safety standards of the manufacturer at stage 2, sometimes parts must be strengthened e.g. clutch. Each stage is indicated which parts are replaced..