pageoneresults is exactly correct. Your Upsolute rep will read and download the files from your stock chip. Then match it with the appropriate remap file, copy that file to the new chip and you're all set. They keep your old file so if you ever need/want to go back to stock they can do that with no problem.

Keep in mind too, that our ECUs and all engine functions are exactly the same as the 2003 SLK 320 and Upsolute has chipped a bunch of them. That's what they used for mine, since no other Crossfires had ever been done before.