There are a bunch of heavy metal versions of "Gangnam Style" on YouTube. But the two best ones stand out because they're in the exact same tempo as the original . . . meaning they sync up perfectly with the video.
--There's a pretty good one on Vimeo.com by a guy named Jessie Wooten. And the newest one was posted on Facebook by some guy named James Woodward.
(--For the first one, search for "Gangnam Style Jessie Wooten Templario." The second one is tougher to find on Google. Just search for "James Logan Woodward Facebook" and he's the top result. It's halfway down his main page.)