I found myself trying to get my suspension on my 09 M1000 162" Sno Pro to work better. As we have had very little deep powder this year I have noticed the rough ride that much more. I tried to tune it out myself but no go. I live in Lynden and know Mark and Matt at Holz. So I called Matt and he said they could fix it right up. Dropped all four shocks off and picked them up the next day. I noticed there were two springs on my front arm shock now and the insides are probably top secret. I installed them put 50 psi in the front and 125 in the rear. Took my pump with me today but never took it out of the sled. So much better!!! It still an M sled in the rough but the shock action is night and day better. I would highly reccomend this for anyone wanting a much improved shock action on their M-Sled.