Can I be controversial? Why do you want a C63? If it's a case of "I must have the top of the range", I or intend to use it around a track, or I love the look of it -then I guess nothing else will do. However, my C350 won't touch a C63 round a track but in the real world where there is a limit to how fast you will go on a public road. My 3.5 litre car can keep up with most people including Boxsters, Caymans and this week a TVR. Given that I'm not prepared to go near my 155mph limiter and given that a C63 gets to 60 only 1.5 secs before I do then on a run I bet I could arrive virtually at the same time as a C63 (awaits incoming!). Road tax is about the same but things like non AMG branded brakes are loads cheaper and mine uses less fuel. Given that £12k would buy a good C350 with 8k left of your budget for mods or a holiday! Oh and there are nearly 2000 C63s in the country and only 99 C350s like mine......just thinking aloud!