Kam - Here's the longer story... So I set up the PopLoc and found 1) that the knob didn't clear and 2) the lockout didn't seem to work. So I contacted RS and sent it back to them under warranty. While there, I had them convert it from 80 to 100mm and get rid of the PL thing all together since it didn't clear the DT. I gave them my CC number for the non-warranty stuff. So I just got it back and they switched everything out and there doesn't appear to be any charges. I checked my CC account also and no charges. They also said that the PL was just not set up right in that there wasn't enough tension on the PL cable. I don't think that that was the case, but they'd probably know better than I. I just hope that the non-PL lockout works! So no answer for you on cost. And KUDOS to RockShox for the work and SUPER-fast turnaround.
As far as difficulty, again I didn't do anything. Besides that fact that you have to tear the thing apart and replace the oil, the actual swap-out looks easy. The whole top knob and damper mechanism is all one piece that looks to just back out from the top. It is a major pain though that you have to take the lowers off. Even more of a pain that you have to do the same to change the travel. I hope I like it set up at 100mm. Anyway... a lot of typing/reading with not too many answers for you!
Agreed on the PopLoc being kinda overkill. Mine's on a singlespeed in Front Range CO. Lock it out for the hour of climbing and turn it on for the descent! S
