If a cam pulley/tensioner was worn, you might get a whirring sound from the left side of the engine, or take the cover off and physically watch it wobbling if it's that bad... Although... sometimes they can be silent and just let go at any time. If in doubt, change it.
As for the flywheel, yes it is a dual mass flywheel on the A3. If it's worn, and by worn I mean, if you have the gearbox and clutch off, it has 10mm of play or more, it would rattle it's nads off on tick over and with sharp revs from tick over and you'll hear all kinds of weird vibrations at different revs while driving too. Hope this helps!
Ben