I would tend to disagree with that. I think the softly-softly approach is the better one to take at the initial stages with Audi CS. They will more than likely be unaware of the discussions with the dealer and it is best to give them the chance to review the situation and come up with a solution of their own accord - rather than issuing threats as that is unlikely to make them want to help out. If after they've had the opportunity to rectify the situation you are still no happier then it is time to go at them with both barrels. You don't want to dirty your bib too soon because the next time something goes wrong they'll be thinking "oh, here he comes again" and will all dive for cover.