MPI ECU with Hot Programming...EPI/HPD Clutch Kit...LTE Fuel Controller...just these few items will put a smile on your face...I tried the EPI Clutch Kit alone and the 70 weights (For a Turbo Snowmobile) were too much dropped to 66 weights standard polaris type and voila she rips...going to try 64's also I used the primary spring from EPI the secondary spring and helix from HPD...still going to try different config's with clutch in future I want all my power used up at 50mph and I want all the horsepower from 0-50 most usable for me and the way i ride...if I want to cruise at 55-60mph I'll use my truck ...