cjw, As far as we know there is no Mercedes that has a 3.55 gear set that will fit in our pumpkin, if you go back and read post # 20. There I was referring to the 391 dear set out of a Dodge Challenger, that with drilling an additional hole in your frame, changing the axles and the hubs, that it would be possible to put a 391 in the car.
Right now the only bolt in swap that we can do because of the size of the pumpkin is a 307 to a 327. This requires changing the ring and pinion only, or of course you could just install a SRT six yoke, on a limited pumpkin, then you have the same thing. If you had a Mercedes junkyard and you had all the pumpkins Laying Side-by-side with the numbers written on them with what car they came out of,and you could compare this to the pump and that is in the crossfire ( either limited or SRT 6). so right now the only bolt in are the 307 to 327 or the 329 to the 307.Hope this clears it up for you.
One other note: being that I and grip already broke the set of 307 gears with the wavetrac, if I break another set, there will be a Ford 9" complete rear in in my car,,then I can put the 355 or any gear I want into my car.. jim