not sure about the preloading thing either...in regards to the launch, you probably dont "need" a line lock, but it is definatly good to have...its good to have the security that the car will not roll forwards or backwards at all, even if the track surface is flat....i dont think i understand what you are saying- you are in first gear bringing up the rpms, yet somehow without having your foot on the brake as well you are not moving?