Purchased my '13 C63 AMG with the P31 AMG Development Package and Carbon Fiber option over labor day weekend.
In a word, this car is..ridiculous.
Cross shopped the CTS-V / Audi S5 / BMW M3.
If you are looking for the best handling car with the best driving dynamics to track on the weekend - buy the M3.
This car has intoxicating torque and the exhaust is a symphony. If you're looking for the equivalent of a German muscle car at a decent price point that will make you smile during your DD time - then consider this car.
Power and torque is readily available throughout the powerband, and the big v8 revs freely up to the redline.
The seats are highly bolstered but still very comfortable for me (6'0 / 195 lbs).
The MCT transmission in Sport and Sport + mode snaps off gear changes in a fraction of a second.
MCT tranny is twitchy at low speeds unless you're in Comfort mode which starts the car in 2nd gear.
The ride is brutally harsh especially in the city, but acceptable for highway driving.
Unfortunately, My car has had to be towed to the dealer twice in the first 2 months of ownership due to a "random misfire" which resulted in the car being undrivable.
The right side cam solenoid was replaced recently with no issues since.