Have drag raced alot in my life and at first you will find yourself rolling out of staging! Backward or forwards and you'll get a line loc system just to stop that. Once you get more serious and realize drag racing is measured in thousandth's of a second, you'll use it more to lift the clutch to the friction point, at the line w/o rolling, so you are not "wasting" any of those thousandth's just getting the clutch off the floor! Some people will side step the clutch (just slip your foot to the left off the clutch pedal and let it slam up!)but I never had the nerve to try that! On the street it's great for traffic lights. I have put them in all my cars.
No car right now...