It’s an interesting thread here with some misunderstandings about the C63 that i want to clarify.

The “normal” performance package (p30) has no power upgrade.

It comes with
• Electronic Speed Limiter Deletion
• AMG Limited Slip Differential
• AMG Performance Suspension
• AMG High-Performance Composite Brakes
• AMG Performance Steering Wheel
(Nappa Leather with Alcantara Side Grips)

Imho the PP version is way to hard suspension wise for everyday usage. Also the 0-200 times do not differ on PP or not, and on production models these times come in the 15 sec range. Here is also a short race (from standstill) between X6M and C63 http://www.youtube.com/watch?v=tzN_EvzFOfQ&translated=1 . Btw this engine is “detuned” and when the "detune" is removed the power goes up to around 500 HP. You can go to evotech (3000 €) or kleemann (2000 €) for this. Brabus is way overrated and overpriced.
The throttle opens over 4000rpm to only 40%, and when you drive the car its feel able that there is some restriction. With chip only you come in a low 14 from 0-200.

The “new” performance package (p30) has a power upgrade. It’s available with December production models, and first tests should hit the road in 1 or 2 month.

It comes with
• AMG Power Upgrade to 487 PS
• Small Carbon Rear Spoiler
• AMG High-Performance Composite Brakes with Red Calipers
• AMG Performance Steering Wheel
(Nappa Leather with Alcantara Side Grips)

Additional are now
• Electronic Speed Limiter Deletion
• AMG Limited Slip Differential

Not available
• AMG Performance Suspension

RC I can recommend you that you buy the car new over tax free sales from Mercedes uk. You can order an german spec car (lhd, km/h speedo, german manuals) and when you register the car in germany, no one knows that the car got on sale over uk. I have investigated the whole process and I can give you details from the uk tax free key account manager mercedes benz when you want. The car comes around 67000 € loaded with new PP and all other needed extras with German tax.