FBO springs

anyone know what the springs from FBO do for advance rate. I got the plate and springs along with a worthless book that is just propaganda for FBO and no real information. The springs came in a bag and no chart or description on what the combinations of springs do. The book is worthless and I recommend not ever buying it, the book is no help in recurving a distributor just a sales pitch. So any real information would be appreciated thanks.

You should call Don and ask him, as he is a nice guy and informative.