My view on my C63:
I have owned it for 2 years, Only use it on weekends and get around 140 miles to the tank, rear tires last maximum of 3/4k, last service cost £1540 which was a big service, i have driven a 335i and could say that the c63 is completely different. 335 being turbo and 63 being NA with massive torque the power is there instantly when you need it. best thing i love about it is the exhaust note (which is addictive) and the throttle response, my previous car to the C63 was a e93 M3 dct and in my view the c63 is a much more exiting car. You won't be disappointed, i can say that the c63 is one of the best cars to own and once you have an AMG its hard to sell it as you never get bored.
Like mentioned before make sure you get one with the performance pack: better brakes, lsd, SLS engine internals, delimited etc. i have had a a dms remap to approx 520bhp with also a black series gearbox map and it transforms the car... GO FOR IT!