http://www.youtube.com/watch?v=DSUSURh2OsI Sounds like a loud tick coming from the driver's side head. It fluctuates with the RPM's. Driver's side cam gear cover is also broken, I don't know what happened to it though. The car drive's perfect, but the rpm's drop all the way down when rolling. Car has CAI and Cobb Turbo back and needs a tune.
Bearing in idler pulley failing? Kinda sounds like that when the AC pulley bearing failed on my friend's WRX.