Mine came in as a rolling chassis (without any trouble!). One has to be very careful, though. It took a few calls to various government agencies, but I eventually learned that both the EPA and the NHTSA, the DOT division, specifically, consider "car parts" to be irrevocably transformed into a "car" once an engine or transmission has been installed, even if it is subsequently removed - kind of like the definition of a virgin (I got the DOT guy to laugh when I pointed this out, and I suspect that is not easy to do ). After that happens, even if it is completely disassembled, it is and will always remain a "car".
Like Tom, I am also putting a locally-sourced 2.3 Duratec into my S3 chassis car. Also like Tom, my car is already licensed for the road. Tom and I are running very parallel paths!