I have a 2001 Gary Fisher Sugar 3+ that has the Cane Creek AD 5 rear shock and Manitou Xvert Super front suspension. I was wondering if there is at least a better - more advanced rear shock that could fit on my rig. The AD 5 is nice, but wouldn't mind something a bit more cush. It can be manually adjusted to go 2.5 to 4 inch travel. Any thoughts?