I think the main reason for this is the airbox restriction (fiberglass insulation) in the U.S. cars. Otherwise, there's not too much difference. The early 76-77 non-cat U.S. cars had the same airboxes as the Euro cars; the later cars had the insulation/different airbox. Of course, the Euro cars had different timing, dry sumps and all that good stuff but, for sound, I think an early U.S. spec car and a Euro car are probably quite close. But you are right, Tommy, no injected car can touch one.