I don't know of a mass produced mid pipe for our combination. I had a local shop weld flanges on the collectors and build a 3 inch X pipe to fit between my current exhaust set up and the flanges on the collector.
Works great and cost about $250.00.
I know Mike (Low50) purchased his X pipe from Kooks. I'm not sure how he put it all together though.
The Kooks headers use a slip on connector, so I just went with the Kooks universal x-pipe. It's a cut-to-fit piece and it eventually fits very well, after the cutting and welding. I love the slip connectors, it only takes a minute or two to remove the x-pipe.
jet-hot coating is $275 extra. they sell stainless steel ones though for about $250 extra.
the kooks x-pipe is $245.
www-completeexhaust-com (replace the dashes with dots) sells magnaflow 3" stainless steel x-pipe stubs for $85 (#10792). they also have a flo-pro 3" x-pipe stub for $49 (#X300). maybe i'll go with one of those. i also want the flo-pro twister mufflers.