Personally I wouldn't pay more than 100 each for clean and sound. Shipping will kinda suck and they need to be boxed well. We got one for Chris that had been dropped from a significant height that ruined the base due to bending one side back about an inch.
I aquired them a few years ago when I put the Corbeau seats in my rig. I ended up modifying my original seat tracks to work with the earlier adapters. I wouldn't do that again though.
I just recently picked up a very good set of Columbia Edition seats to put back into my rig, but the driverside does not have fold and tumble option.
I was going to try and swap everything over, but it's not worth the aggravation.