So, I've been chasing a weird High RPM vibration, about 6500-7000 rpm it vibrates a lot, and its engine speed dependent, but alongside that comes this random clacking that eventually goes away while its idling. I've replaced the Harmonic Balancer already as I found the old one had a chip in it, The Tensioner has also been replaced along with the serpentine belt, could this just be one of the other pulleys? it's a very odd sound.

 

Not sure that it's similar, but my N52 had a much worse sound, along with serious misfires when one of my DISA valves (the "outside" one) flap broke away and was floating around inside the intake manifold. It could be that yours is only partially detached, I suppose.

Here's what mine sounded like:

 

My disa valves are both fairly new so I wouldn't think it's those, doesn't hurt to check though.