Huge acceleration and track speed gains. Much better all-around clutching performance and feel. Quicker back-shifting (down shift). More consistent clutching that holds RPM. Lower clutch temps and longer belt life. Easily adjustable for fine tuning. Includes Goldstar magnetic adjustable clutch weights, primary spring, adjustable torsion conversion helix, and a torsion secondary spring. Includes setup guidelines for model and modifications. 2-stroke models with engine reverse may have an issue when engaging reverse drive. Must slowly and easily engage the clutch when in reverse. Only try to use reverse under light load situations like off the trailer, or on flat ground. Harsh engagement or high load situations can cause the clutch to miss the reverse notch and drop the belt to the bottom of the sheaves..