Just saw the episode with Hammond driving his '67 GT350 and a new GT500 the other day - he definitely has some nostalgia for American cars. And Clarkson had a Ford GT that he was drooling to get for months, so he's definitely not opposed to all American cars carte blanche, even if he had a ton of problems with the Ford (like that's a surprise
).
I agree with others above that they'd find the Camaro generally 'unrefined' and 'crude', but overall I think they'd like it. But I think the Stig could pull a nice time, and they'd respect that. They'll probably crack some jokes about Americans and poke a little fun at it, but be generally positive.
Oh, and Clarkson would never say 'garbage' - It's rubbish, of course! :P