The 2-step limiter can help on the launch but is not nessecary for the hobby racer. It allows you to dial-in the launch perameters and establishes a baseline set up. Ideally you set it at an RPM that will minimize tire spin and still allow the motor to maintain speed when the clutch is dumped. The slip is transformed to the clutch and no the tires, allowing a faster 60ft time, or so the story goes. Buck for bang, how much do you want to empty your wallet to impress your girly friend?