but seriously it could be a bout a billion things.
I agree with that. only one thing to do and that is to have the dealer check the codes with the 1552 or get a vag-com (lap top version of the 1552)
YOu can buy the cords and software so you can use vag-com on a lap top for about $200-$300. Then you just have to become framilar with it.
why are you going to be sending the turbo out for replacment? you know the If you have less then 100000 Miles it is covered under warrenty. And if its boost numbers have fallen off I'd be checking for boost leaks first before replacing the turbo.