I have the IC one. Having to replace the chuff might not be a bad thing; there is some point when increasing the speed, the rate and volume of the chuff changes noticeably (of the original sound system).
No problems with its operation, but I have more than once had the cover on the rear drop to the floor when I flipped the engine over, probably because I was looking for a switch that was under the cover. Oddly, I cannot ever find damage to said cover afterwards.