Just got a catalogue from Elite in Rainham (http://www.elitedirect.com) and they do twin outlet exhausts (one either side of the car) by Remus for about £350. I think this would look 'right' on a CC.
Only trouble is that it's the sort where the pipe from the engine goes to a silencer on the left, then one comes out the back while the other comes out the other end, goes across the car to the right and comes out of the bumper there.
IMHO a more efficient, free-flowing, design would be to have the pipe coming centrally down the car then split via a 'Y' into two separate silencers. TBH I'd prefer to get something like this knocked up by someone like Hayward and Scott than go for the Remus design.
Thoughts?