Jokes aside from my last post.
Something between:
It's a shame that Jeremy Clarkson is a Forza exclusive. Still, I don't think his acid sense of humor would be cool in GT.
Tiff Needell with his paused British accent (I like how he says "five hundred horsepower" while he curls his shoulders for some reason.)
Morgan Freeman (simply epic)
David Attenborough, and they can include the really inspiring instrumental music from his documentaries.
Sir Ian Mckellen.
Really, anything British, except if it's Morgan Freeman.