Like the G_Man said stay the hell away from the Gwaegens and any of the other exotic or rare models on the benz line. Keeping it simple (by simple I mean popular in the US) will give you a hell of a lot less problems and net you a decent car.
Also if you're bringing in the car for your personel use rather than to sell of for a profit (like some people think) you should be ok. Check all local applicable laws before you proceed.
The most difficult part is getting a piece of paper that certifies that your car meets US standards (most benzes after 86 do).The NHTSA has a good preliminary description of the process. Go here:-
The question you should ask yourself is do you have the stamina for it all. If not then buy the parts as somebody suggested, Customs barely would even ask you for an ID in that case.
88 230E (W124)