I had my headphones on at 4% and I had to turn that down...
Wow. That was loud. Hasn't got anything on a Viper though.
From my experience of talking to Americans, if they are talking to a European and said European speaks in British English, they don't bat an eyelid. Same the other way round. If I'm talking to an American, I don't particularly notice or care when they speak in American English. I'm far more likely to notice if someone is speaking Scots or in a strong northern accent, to be honest.
Gas is an ambiguous term here because to most British English speakers saying that you run your car on gas will bring the assumption that you either run your car on natural gas or on LPG, and therefore gasoline or petrol is preferable terminology when crossing dialect barriers.