The idle bounce could be a number of things but I would get the throttle body cleaned first then test for vacuum leaks.
The rattle could just be chain tensioners.
I have no direct experience with IMS bearing failure but you will have a significant leak on the underside of the motor, then at some later point in time there will be nasty grinding sound just before the motor chews itself to pieces.
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Jäger
300K Mile Club
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