vessproms

I checked out the mufflers and couldn't see any vacuum line on it,only c63s come with valves or is it an option

MarkC63

It's an option on both (might be standard on some C63S depending on the country)

shoe3k

The center section comes with a flap on all c63. The performance exhaust adds different mufflers that incorporates flaps and an exhaust button on the center console. I know some countries have strict decibel requirements and can't answer anything specific to that.

Uga Uga

Sports exhaust is standard for all C63 Coupes in the UK.

J.M.G.

As shoe3k already mentioned, the C63 has two different exhaust options:
1. Standard - with ONE Exhaust flap in the center H-pipe
2. Optional - as standard PLUS an additional flap in each rear muffler

These flaps are computer controlled to meet all (noise) emission regulations. The optional exhaust has a push button (center console, below the volume knob), where the driver can demand for more exhaust noise. However, this does only effect the muffler-flaps and does not effect the H-Pipe-Flap. Also the computer can still override this demand in certain situation (engine load / speed), to meet all regulations.