The actor playing Owen Wilson really nailed his voice, plus props to whoever found the dead-on wig. Not to mention everyone else involved for hitting this out of the park, because I'm convinced that if Anderson did decide to do a horror film, it would look and sound a lot like this, especially the choice of songs.
H/T to TV Tattle.
Updated 11/8/13: Just found this "How We Did It Article" by SNL staffer Alex Buono. Thanks again, TV Tattle! I didn't even realize "The actor playing Owen Wilson" was actually Edward Norton. I didn't recognize him at all.