BMW M8 Competition versus Mercedes-AMG C-Class C63 S (W205). 0 points of retained value between them.
The numbers make a compelling case before you even turn a key. The C63 S cost £132 per horsepower when new against the M8's £200. It weighs 250 kilograms less. Yes, the BMW is faster to 62, but the gap is seven tenths of a second, and the M8 achieves that through brute computational force rather than anything resembling driver involvement. The C63 S gives you 503 bhp in a car that actually wants to rotate, slide, and surprise you. That is a fundamentally different transaction. Character is worth pricing in. The W205 C63 S is widely regarded as the last of the genuinely unhinged AMG saloons, before Stuttgart decided everything needed to be smoother, safer, and more algorithmically pleasant. That cultural moment is now closed. You cannot buy a new car with this personality at any price, which means low-mileage examples of this generation have a floor under them that pure depreciation logic misses entirely. Neither car has sufficient auction data to call a bottom with confidence, but the C63 S has the stronger case for holding value as enthusiasm for the old AMG formula solidifies. The M8 Competition is an extraordinary machine in a straight line and an effortlessly luxurious motorway companion. But at today's used prices, buying it over the C63 S means paying significantly more for a car that most experienced reviewers find less rewarding when the road gets interesting. The Mercedes is the smarter purchase and the more honest performance car.