GaryH said:
Im sure i read somewhere that the Z4 being built in Carolina has uber sensitive emissions sensors due to the extra stringent emissions laws out there, so while it may fall foul of the law in the US of A, in the U of K, it would be "very clean" or something along those lines
I laughed at this - just because I've never heard anyone say the US has strict... anything - except maybe Food and Drug laws (FDA).
Basically there are no emission laws in the US; except the state of California. They set up CARB (California Air Resources Board) and anything with an engine has to pass their regulations (only emissions mind you). In fact, some models of cars are made in two versions for the US - one for California and one for the rest of the states.
Once a car is sold as new here it's never checked again for emissions. Actually I don't think they are actually ever checked, we just take the manufacturer's word that they are ok. People routinely remove their catalytic converters for "more power" and since we don't have MOTs (again, except for California - and that's only when you purchase a used car IIRC) you can pretty much do whatever you want. No one checks anything, ever.
I've always thought MOTs were a good idea judging from the crap some people bring onto the public roads, let alone the highway. There are cars that are actually MISSING PIECES like bumpers, taillights, entire exhaust systems, windows, etc.
It's a hell of a place. :|
), but it would appear from what you've said that people actually drive around in cars like that 
