When it comes to lightening a stock flywheel there is only so much you can take off before it comes unstable and thats not enough to notice a difference, and also if is not professionally done(not balanced or shaved too much) your flywheel will break apart and destroy your tranny and motor. I have seen pics of this and the motors were destroyed. When your looking for a weight it all depends on you. If you go real light like 8-9 lbs you will rev up fast but downshifting at first will be weird do to your RPM's dropping quicker. Some ppl don’t like this but I got used to it pretty quick.When you go up to 12lbs there is not that big a difference but daily driving is easy.