The only extra part required is a clutch assembly to obtain a complete race transmission system. If an exhaust is used with a cylinder that between them generates a wider powerband then the only transmission part required is an upgraded rear spring so that the belt slip is eliminated. The most popular aftermarket exhausts are those supplied by Technigas in several different styles. These come with rollers so the transmission works in the right range. The Technigas exhausts are very reliable, improving both top speed and acceleration.
Clutches are available in two and three shoe types.
Aftermarket springs are used to alter the biting point when tuning the transmission. On higher states of tune where enough slip cannot be generated by the springs, aftermarket clutches are available that have a choice of springs and lighter shoes to give more adjustment. The ultimate clutches are Polini Speed Clutches and Malossi Delta Clutches. These have a choice of springs, spring positions and moveable weights to allow the clutch to work with any motor from standard to full race. Cylinder kits are available in several formats, basically cast-iron with or without cylinder heads, road aluminum with cylinder head and race aluminum with cylinder head.