Well a lot has been suggested but to me, hearing that vid made me sure it was exhaust related. You have a spare header you can throw on it? those header bolts are notorious for coming loose and falling out, make sure every one is good and tight(do not snap one it sucks) put the car up securely and pass your hands near the header/h-pipe junction and see if theres any air coming out. Probably isn't this but it oncce was on my car, started to hear a bad noise sounded like a lifter ticking or scraping a guide with a pushrod, turned out to be the tensioner dying. Check the plugs for cracking/looseness, check the vacumn lines for cracking and maybe block off the emissions lines connecting the heads if you havent already. My 2.5 cents
Matt
