While in for my 20k service I had the Progressive cartridge system installed instead of a fork oil change or other mod to the plunger setup. (about $700 parts and labor! really 4 hours labor to drop in these units? ah well). Anyway, I put about 200 miles on it so far on highway, two lane, single lane, smooth and rough. I guess I am a little disappointed I dont feel a big difference in handling on the big beast but its also hard to compare when the last ride I took was 2 weeks ago riding it in to the shop (was away for work in the meantime). dive under braking is much less and bounce is also more controlled/lessened so I know its working well I just had hoped for some more change in cornering control and such. I think perhaps weight and the rear lack of damping adjustment might be limiting it now but rear shocks are not something I am tackling right away. Anyway for those wondering about these units they are slick (drop right in) and do help with front end dive and do control bounce in the front on uneven surfaces without being overly harsh but they arent the end all of handling improvements for the big dude, just a beginning.