I'd be willing to bet that the guest is Jon Favreau....
http://www.imdb.com/name/nm0269463/
That makes sense because he's directing a movie about the history of American hot rodding following WWII.
I'd agree with the previous post that the one guy is Bruno Massel Jr. Here's the web site for his father's drag racing parts business....
http://www.brunosautomotive.com/About Us.htm
I also think that Johnny Fairplay is a good guess. Here's his MySpace page, lol.
http://profile.myspace.com/index.cfm?fuseaction=user.viewprofile&friendid=38577301
The third guy I can't find. He looks like a former football player (American football) but I can't place him and having just the name "John" to go on doesn't help.
As far as the show goes, I think their set in the one picture from the magazine looks like it was shot at a flea market...not good. And I think its a mistake to film the show without an audience. There is no way that it will be 25% as good as UK Top Gear but the question is how bad will it be?
As far as the show sucking becuase American cars suck, what percentage of the cars driven on UK Top Gear are British? With a few notable exceptions most of the "exotic" cars are available in the states and while I enjoy seeing the small Euro hatches is that what YOU really watch Top Gear for?
The two things that will matter are the Presenters and whether or not they shun coporate sponsorship. If the hosts are decent and are given the freedom to say that the new model "X" from car maker "Y" is a total P.O.S. then it will at least be watchable.