On the Jalpa the difference is next to zero. The compression ratio, cams, etc are the same. Lamborghini just didn't make many to start with, and a tight budget prevented much difference. On other cars like Ferrari & Mercedes the difference can be big. The values typically are different on those also - the euro car is worth less, and can be MUCH harder to sell. Ferrari dealers cringe working on euro cars. Mercedes used cheaper interiors, and had less crash protection. I know a guy who imported 5 Mercedes in the late 80's, all euro cars. He told me he lost a little over 20k getting them to pass, and then had a whole rash of problems after he sold them from the people who bought them. Mercedes wouldn't honor the warranties much less work on them. Euro is the nice word for grey market.