lightweight flywheels just helps the engine bring more hp to the wheels. for rally and road racing, the lightest flywheel would be the best advantage. but in drag racing it will effect launch. it just helps rev faster and also respond quicker to clutch engagement..therefore, low-torque high revving engines sometimes need the mass of a heavy flywheel to launch more smoothly rather than bogging down off the line. <-- that's what i know about how the flywheel will effect ur car..clutch ware just depends on how powerful your engine is and what type of clutch you're using..obviously, the more power your engine puts out, the more hold your clutch set should provide.