The vehicle must be compliant to US specs and that is emissions, glass and windows, some body re-enforcements, bumpers, lights and other little things in between. When I lived in Germany there were a few vehicles I wanted to bring back with me but the laws are very strict on that matter. Even the oil that European market vehicles use is different when it comes to European vehicles for the American market.
Read this on the oil issues.
European import cars motor oil specifications
Someone even told me that European market vehicles are better balanced (engine internals) since they are most likely to be driven at higher rate of speed when compared to European cars for the American market.
And no, you can't fool anyone because as soon as the DMV types the VIN number for the registration is going to raise a huge little red flag.