Halloo. Ja, the "vos" as some call it switches the ignition to a more advanced postition at idle and part throttle settings. On a stock or nearly stock motor it can improve part-throttle response, fuel mileage, and decrease exhaust emissions. As you start running more compression (as static and dynamic go up) the vos can actually cause problems such as detonation at part throttle, idle problems, and just generally make for a good (or bad) day in figuring out a good ignition timing curve. If the motor runs good or better with it hooked up I would leave it hooked up. Angel does not like the vos, but she is at 10:1 static and tends to "ping" with it hooked up or when the gas isn't all that kosher.