S3 making odd noise on acceleration - normal?

[RacingTeatray]

My S3 has started to occasionally make quite a loud blaring noise under acceleration (particularly if I'm in a slightly high gear for the revs) which sounds almost as if the exhaust has a blow somewhere in its front sections. However this seems a bit unlikely given the age and mileage (2.5 yrs old, 25k miles). Is this normal?? My old TQ never made such a noise so I was just faintly worried that something was amiss. Doesn't seem to affect the performance, just sounds noticeably odd.

Does anyone else have any experience of anything similar?

The car is a completely standard 225.

 

[RacingTeatray]

I take it no one has a clue what this could be then?

 

[Drill]

Does it sound like someone blowing on a Coke can? Could be the DV or a boost hose loose (Leaking) /ubbthreads/images/graemlins/confused.gif

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