After a week in the alps on the summer my shock appeared to have air in the damping circuit. So because I have an issue with allowing bike shops to work on my bike I cracked out the manual for the monarch plus shock and set to work.
I have kept an eye on the shock market since I bought this bike as it came with an auto sag air can, which broke within about 5 rides and has subsequently been replaced (by specialized) with a debonair can. Usually shocks come in 216x63 but the specialized specific shock with the proprietary mount is 216x57. When I had the shock in bits there was a black spacer on the damper shaft which is there to reduce the travel from 63mm to 57mm.
There are no clearance issues with the frame. I understand the warranty may be void if I do have any problems.