I’d be interested to know if anyone’s heard the same reply from Audi dealer regarding strange noises coming from the exhaust system on A3 1.6 SE (102bhp) when started and revved from cold:

Dealer response:
“Flat/wheezing noises come from two blowholes (or drainage holes) machined in the exhaust system (one in pipe/one in back box)" – Apparently the same exhaust system is used on all petrol 1.6 & 1.4’s and they’ve had a number of complaints about them.”

I had dealer source another 1.6 and put it side-by-side and it does have a similar sound.

Noise sounds as if a seal has gone near the engine outlet manifold and would explain why it is less noticeable when vehicle’s fully warmed up. If they do put two blowholes in the exhaust the next question is why only on the 1.6/1.4 petrols and not elsewhere? Also – why would the noise suddenly appear (after approx 3-4000 miles from new)?