if you think about your next upgrade, you should consider the new IDM clutch:
I used this clutch at the last race and I am totally amazed by it. It's tiny. The weight difference to the normal Mugen clutch is about 20 grams, which feels like a ton in acceleration.
Due to the hinged fly weights, it hit really hard if needed/wanted and it was absolutely consistent during the 30 min main.
Also, the clutch bell has four bearings instead of 3, which makes it spin true and very free. No play anymore.
I don't know if XS Power is importing them, but the sure ought to!