Spo123, yes I know about the Euros not having turbos that it why I said " You could even have a US turbo engine installed if you wanted!"
Actually I once spoke with a German fellow that said there are some W123 turbos in Germany, they are rare and probably the product of someone like myself that has a modified car. Thanks to the way the common parts interchange. With some exceptions, like the exhaust valves in the Turbo are Sodium filled. The turbo engines have slightly less compression ratio than the non turbo, and I would expect the Euro engines to use a different cam, the gas cars usually always use a hotter cam the pollutes a bit more than those cut for the US market. Performance is the key spec for the Euros, and it is possible the IP is different but likely only internally in a few areas, You can always get it rebuilt stateside, Bosch keeps good records on parts for repairing their IP's - they make dozens of different models!
As for the grey market questions especially related to the tranny, you really need a person that has loads of experience with those here in America.
I recall someone steering me to a MBNA dealer's shop in VA that was supposed to have such an "expert" but when I reached that person he informed me that I could NOT install a gas engine frma car with an automatic transmission in my 220 (already set up with a stick shift) - my friend Larry at MB Garage, a local outfit, did it no-sweat. The pilot bearing was one item and the flywheel had to be swapped - real easy actually. To heck with the dealer, if I had listened to him and not bought the car I wouldn't have my lil puppy the 220 (I love that bugger!)
You better start calling around before that car gets sold! Like I said, you can buy it and run it till the engine dies then have a turbo engine stuffed into it!
Dieseldiehard
1971 220 4-spd manual 104646
1979 300TD w/ ’85 turbo engine 290820
1983 300D 238890
1985 300TD 207980
1976 300D (still waiting to see what it needs to get running!)