If you are going to be drag racing an lighter flywheel may not neccessarily be the correct decision. As everyone knows a lighter flywheel will help the motor spin up faster, removing the rotating mass always does, but with less centrifugal force means the motor will slow down faster, for lack of better words. Light flywheel = less gas to get it moving, more gas to keep it moving. Heavier flywheel = more gas to get it moving, less gas to keep it moving. If you launch with a lighter flywheel you would have to launch at a higher rpm to keep from bogging the motor. Same would go for normal driving conditions, you will find you will have to give the car more gas to "creep" forward with a lightened flywheel. Generally a heavier flywheel for Drag racing, and a lighter flywheel for Auto cross or road racing.