After my Skreem module went out in my '05 Crossfire I exhausted all of my options and tried just about everything recommended on the forum, but it was clearly dead.
I towed my car into CFI Services based in New Orleans, Louisiana and they had it fixed in exactly a week for $500.
The owners know what they are doing, and have plenty of experience working on crossfires and Mercedes, and is one of the only people in the area with the right tools to do so. Unfortunately they do need the entire car to do the repair, so don't ask about sending parts in.
So, for all the crossfire owners in the South that need their Skreem fixed, I highly recommend them!

CFI Services
5720 Heebe St
New Orleans, LA 70123
(504) 734-8200