I have used them on two different GG 250s. They lower the rear about 10 - 12mm, but add leverage to the linkage in the initial part of the stroke, and tend to make the bike move through this initial travel quickly. I liked them on my old '00 XC because that bike had a long shock was a little more "stinkbug" than my '03 and '07. Honestly I wouldn't use them on a newer GG as the bikes are balanced well as is. If your looking to calm down the rear more just don't run so much preload (10mm max) and go up on the spring if necessary.