wow that much to replace CC these days! are they sure it's the CC? I haven't tried those "magic fix in a bottle", but last year when our toyota was losing power on uphills and keeps the EGR overheating, I disconnected the muffler first, drove it and it's the same. next I disconnected the CC and I saw the cells inside kinda look like inside a beehive... it's totally clogged! drove the car w/o the CC and power was back! so I ended up buying an aftermarket CC online, oh! and some gasket. if I remember it cost me around 200 plus shipping and I just installed it myself. on mine there are only 4 bolts and it's out, but if you got rust in there, be ready with a grinder. sorry I know I didn't help you with your question, but I can't imagine how a liquid in a bottle can help unclogged those pores, I can't even push those clogged materials with a stiff wire.