I am leaning towards the C63's design. I saw a CLK63 AMG Blackline driven by a 20 years old chick today. Hot.
I agree with him, the AMGs are nice and fast but the corner abilities are nowhere up to par to any Ms.
He won't be able to legally experience the superior handling of the M on the street anyways. If he takes it on track the AMG blackline's performance would provide more than adequate fun and thrills. In a non-racing application, the 5-15 seconds faster laptime is really more for bragging rights than anything else. Driver will be the biggest flaw there.