Started out with the BUKU Clutch and determined it was like Velcro shoe laces. Easier for the lazy and uninitiated. After utilizing the web to download BUKU tuning information the progressive nature of the engagement is certainly a good tuning option but I just didn’t understand. Moved to the stock XB9 2012 kit set up and the car was way too boggy. Tried Kyosho blue shes and 1.0 springs and this made the car great – for awhile. The shoes mushroomed and started dragging on the flywheel. I personally think they need thicker washers against the flywheel.