Audi 5000 s Vibration

[deva100w@wonder.em.cdc.gov]

I just acquired a 5000s at an auction. I find that the car engine vibrations at idle 
seem to be excessive- I have never owned an Audi before so I don't know if this is 
normal. Is there a description of "normal" levels of vibration? A couple of 
mechanics who looked at the car and drove it during the past few weeks did not 
mention anything was amiss with the vibration level. They didn't find the loose 
spark plug either, but that's another story!

I would appreciate any words of wisdom that may be offered by others who have 
travelled this path before me.

Thanks,

Jay