Whats this rattle?
 

Since a few fast track laps, my MY99 has developed a noticable rattle/clatter, mainly at idle that doesn't seem to increase with revs. It is coming from the turbo/downpipe area.

I've eliminated the heatshield by removing it and still hearing noise as strongly as before.

Any ideas or relevant experiences would be appreciated...

The down pipe is also bolted to the gearbox bell housing and gearbox cross member, check them too.
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