I have c/o's now and using zukizzy from Pirate to help me with my valving. I've only revalved once so far and the performance increase is drastic. I've picked up roughly 20 mph on my test course just from that one revalve. I'm really looking forward doing more. The changes make a big difference, more than I ever would have realized.
It makes me think back to my airshock days and wonder how much I could have picked up had I bothered revalving them. The valving that came in my c/o's in stock form was SO FAR OFF from what is netting me huge gains right now. I guess they have to put SOMETHING in there and they have to sell their shocks with what will work best on the most rigs. But at the same time it is amazing to me how far off that can really be, and my rig isn't that unique in terms of weight and distribution.
NO ONE bothers with valving on airshocks. I don't know why. But I bet there are huge gains that can be made there, too. I almost wish I could go back in time and do some valve changes on my old rig, see how good I could have got it. Stuff that is standard operation to me now would have been impossible in my rig then. I really feel like I missed out on a lot of what I could have had with those airshocks and most people mess with them less than I did! I guess they kind of get a bad name since they are the bastard step child of the c/o and so many people regard them as a temporary or half-step to the c/o's. But I bet with true tuning they could hold their own with c/o's, at least for trail rigs / rock bouncers.