What size bushings when upgrading rear shock?

Murvalous Posts: 56
edited January 2010 in MTB buying advice
Ok Im uprating the rear shock on my Specialized Pitch FSR Comp 2009 to a Manitou X3, it doesnt come with bushing but how the h*ll do I work out what size bushing I need, there is a HUGE list on CRC :(
Live just by Wimbledon common but still a beginner