Thankfully Leno turned down the offer, not because he's unworthy, but rather because he knows he couldn't do the show justice and because the idea of an American Top Gear is doomed from the start. Being part of the BBC, the original version is not reliant on advertising to stay on the air, so talking smack about a particular automaker and its wares is no biggie. As Leno notes, things work differently at NBC and any episode in which a sponsor gets lambasted would immediately be followed by what The Tonight Show host calls, "the meeting". And then, bye bye sponsors and bye bye show.
Read the full article here: http://www.autoblog.com/2008/03/31/leno-fears-top-gear-usa-may-suck/
This is so true as it is evident on other car shows on Speed and other channels. These shows are all created to advertise and therefore the hosts are always kissing ass. I have yet to hear honest opinions from the hosts on these shows. All they talk about is how good the cars are and never do they say anything even slightly negative.
I really hope NBC will keep the auto manufacturers from sponsoring the show so the show can remain true and objective.