Im installing a Stage 3 and 7lbs FLywheel next week, the cost difference is marginal, as i Live in australia the biggest difference is the Shipping... i recently burnt out my Thurst bearing, so i may as well replace it all while im under there... and stage 1-2-3 Why would i want to replace a stock with a stage 1 if at a later date im gonna change it again... *laziness lol*