Ya need a flywheel puller to remove the flywheel & then it's as simple as swapping out the woodruff key. Lightening the flywheel will make the engine a lil more rev happy but at the sacrifice of the momentum that the heavier flywheel carries into the next gear after your shift. It really comes down to the type of riding you do, if you're a woods/trail rider ya mike wanna leave the weight or find a happy medium where ya don't have as much weight removed. Some guys on here have done it though.