Re: Engine rattle noise !Blue smoke...!
Loose bolt on the intermediate shaft results in rattle up to certain rev range (1.8-2.3k or so) depending on how loose that bolt is.
I had this in my 996tt so I know for a fact. I had to dismantle and blue print the engine at my own cost to avoid the engine blowing up. The only positive thing from this exercise was that fixing this problem and consequently blueprint all engine parts resulted in a much much better engine.
Insist on proper inspection, escalate it as much as you can.
For the 996tt cars they changed a few engines in the beginning and then they stopped since they saw that only a small percentage would actually blow up.