I believe the 170 bhp V5 is fly by wire (no throttle cable - the earlier one like mine has one). My revs normally sit at 700/750 at idle so I can imagine 600 seems a bit low, although with the V5 you do of course get a slight burble.
It could be the potentiometer (might throw up a fault code on VAG com). I was told a sign of this being faulty can be to look at the revs when you switch on. You should see the rev needle blip upwards before it settles - don't know if this is a reliable test or not?! Of course another sign of problems is if the revs vary at idle when warm. When the MAF fails (common) it can also affect idle revs and adversely affects performance.
Hope the new cars OK other than that and that you're basically enjoying it.