Please note:
Retrofit systems usually have more power than the original exhaust. In order to obtain an approval, they are throttled at the factory, which can result in a shift of the power band.
In order for the scooter to reach its full power and speed, it may therefore be necessary to adapt the engine to the new exhaust with other variator weights and/or clutch springs, even if it is to be used throttled on a production engine.