I forget what you call mufflers... something box?

Silencers

What are sedans called?

Saloons

I had to look the American words up on here: http://www.scit.wlv.ac.uk/~jphb/american.html

Though it doesn't have chivvy, wonky, or to have a benny, all of which drew blank looks from Sonic Blue types who came over from the US office a while ago. And I won't soon forget the look on the faces of the forty or so engineers at the US office when Mike said, in the middle of a presentation, that he was teaching their grandmothers to suck eggs.

Peter