Before I purchased my US spec '92 500E I looked into importing a 500E from Germany. With a price of between $10k-18K for a 500E in Germany it certainly seemed worth it. A ship from Bremen with insurance is less than $1000.
Both MB and BMW have made it clear that they will not provide a letter stating that both US and Euro cars are the same.
I spoke to some Importers and the cheapest "conversion" quote I could get was $8000!
So it just wasn't worth the headache and subsequent lower resale value so I told my cheapside to take a jump and paid $30k for an immaculate black '92 500E with 59K miles and full history. Oh, yes and its brilliant!
PS There is a 100k mile car for sale in Pa for $25K if you are interested.