Is this noise normal?

[specbuild]

Just thought I`d throw this out there as I`ve noticed there is a lot of knowledge available thru this site.Have just purchased a 2011 MPS Luxury.Being of mature age and a virgin when it comes to the turbo scene,I have noticed a noise coming from area where the turbo is situated.After giving the engine a rev to about 2.5-3000rpm.as the revs slow down to normal idle,there is a "whirring" sound that lasts for approx.20 seconds.Is this the turbo slowing down or something more sinister?Being "old school", it sounds like bearing/bearings failure.Remember,I have only just picked up this car and it has only done 40km. I know if this is to become a warranty issue that my first port of call is back to the dealer but I`d like to have some ammo (information) available to me when the Service Manager gives me his feeble diagnostics.Any info will be much appreciated.

[Jmac]

Does not sound familiar to me mate, is it audible from inside the car?

[specbuild]

You can`t really hear it inside the car but definitley when the bonnet is up.

[Caffeine Fiend]

Can you post up a vid with the audio?

[specbuild]

Have tried to record the actual sound but it becomes virtually inaudible and cannot be distinguished between it and engine sound.

[Nhut]

it could be ur air box

[Rayd]

i think i know the sound your talking about, ive noticed this on a few MPS's it sort of sounds like a distant police siren , freaked me out a couple times actually... im pretty sure its normal.