Aside from the usual pad wear warning lights, as far as I know there is no wear indicator. Standard Mercedes servicing will give you a video and measurement of pad thickness, but in general CCB will outlast conventional brakes by a considerable margin.
I have a C63s on order with CCB, and I have colleague living with a C63s Wagon for 3.5 years and covered 40k miles and the first pads were changed around 32k miles (not a track car). Even with track days, carbon discs should be good for 75-80000 miles plus. They are however quite brittle, so errant tyre fitters chipping the disc or flying road side debris being caught in between the pad disc may severely shorten their lifespan.
The biggest bonus of CCB - Very little brake dust even under heavy use.
Also, only the front discs on the C63 are Carbon Ceramic, the rears are steel. Genuine front discs/rotors can be had for around £3700-4000 for a pair, there are number of UK dealers that sell on line and even more Germany MB parts sellers on Ebay that sell genuine parts at respectable prices. The pads are not much more expensive than standard AMG ones which everyone seems to whinge about anyway.
They do (CCB) eat brake pads on track days, and the usual complaints of squealing brake pads and endless conversations about pad material abound the internet.
You can buy a set of genuine MB Carbon rear rotors from an MB specialist in Germany for about £2500, these are E63s rear discs apparently, the hub fitting is adapted slightly for C63s (don't know how). I will try and find the link I was emailed and post it up. It does make more of a difference in feeling apparently, albeit an expensive upgrade.
Regarding the pricing, the Edition 1 (it is effectively an option pack) was sold in low but not limited numbers, so the rare factor should not inflate the price that much. Before the 2019 WLTP cars were released there was a spike in prices, quite a big one as people were worried the new cars wouldn't sound as good, hence what you might see as discrepancy between what the dealer wants and the book trade and resale values. Without telling us the mileage/HPI/service history and number of owners its a stab in the dark. I have seen a few of these that seem to change hands very quickly, 2.5 year old cars with 3 owners already.
My two penneth... the dealer is trying it on and I personally wouldn't entertain a car like that from a none MB dealer unless they were a Merc specialist, but the old 'buy on condition' rule almost always applies.
I'm not exactly sure, but if it has a full MB service history you should be able to purchase an extended warranty from Mercedes AMG, might be a bit better than a third party one?
