Fisrt off not sure if this should be in this catagory or "general" but my thinking is if done properly it's a performance enhancing mod.
Anyway after getting my forks completly disassebled, (thanks to all and especially Z for the great "how to" vid)I noticed that the spacers suppiled by Progressive were the wrong size. In the kit they shipped out the spacer is only 4" long and for the America/Speedmaster application the spacer should be 6.12" for a 1" drop and 5.12" for a 2" drop. These said PVC spacers DO REPLACE OEM spacers, also to do this properly you must remover the dampner to ADD the required springs. Here again 1 spring for 1" drop and 2 springs for 2" drop. Yes you ADD, meaning the OEM spring on the dampner stays in place.
At first I thought that I must have ordered the wrong kit but upon speaking with Progressive this am they have been sending out this kit with the wrong spacers. They didn't say how long it has been this way but are in the process of correcting it. So my suggestion is if you have lowered your front and it's not exactlly what you expected you may need to go back and measure the spacer to make sure it is the proper length.