If its still not out in 6weeks consider what I am doing X pipe and 200cell Catalytics.

If you want I know of a manufacturer that produces a custom exhaust to the exact spec's you want the only problem might be language because its a German Exhaust Manufacturer/Maker.

Here is info copied from member OWL SLK at SLKWorld forum

"Stueber is building handmade exhausts for your wishes. Very exclusive but not very expensive. The quality is on the highest level you can get. An extraordinary company which is living without any selfmade public relations.

http://www.stueber-auspuffanlagen.de/index2.html "


Hope you get what you need