alfaromeo, what do you mean by sound like a super charger?
Do you mean it wines or whisles?
My coupe wines at really low revs when crawling along, but soon as you get above 1500 revs it goes, im told that happens to alot with many 20vt's.
If you are getting a whisle low down off boost then id say that maybe its not supose to do that.
Cant say for sure till i here it so if you want to meet and compere you have got my fone number.
If your that worried tho i know a coupe/italian specialist near the town center.
Have you heard of motermech?
One way to elimenate the induction kit fromthe enquiry is start you engine and take of your induction while it on idle, see if it sounds diffrent or whatever.
Or just put the airbox back on, start your car and see if it sounds any diffrent. you can put the induction kit back on after.