Bag of nails

[morris]

Evening all.

I've now got my exhaust system installed on my M50 and unfortunately, now that I can hear the engine rather than just the roar from the manifold as previously, it sounds, well, just horrible. Take a look at this short vid

https://www.flickr.com/photos/58068042@N07/15370329065/

I'm hoping that this is just down to it only having been run for short (30secs to a minute) bursts over the last year or so to demo the beast to friends etc and needs to be run up to temp to settle down a bit. I've topped up the oil as it was on min but that made no difference. I guess after a warm up test the next steps are:

1. check none of the spark plugs are loose and maybe stick some new ones in anyway.
2. check for misfires. The plugs are the originals and I could unplug each coil one at a time to find an offending cylinder
3. Torque the manifold up a bit more though I'm reluctant to do that and risk stripping the threads on the head.
4. something else? I'm open to suggestions

I'm pretty sure it's not the hydraulic lifters as you can hear the valve train chattering away much more quietly in the background and vanos rattle is usually much less rhythmic. I also think it's way too loud for injector noise. I'm just really hoping it's not a bearing though I think that would be even louder and be pronounced under rev'ing where as this noise seems to settle a bit after rev'ing.

Does anyone have any other suggestions on what the best next course of action is?

thanks
Ian