It definitely sounds like turbo boost pressure leaking from one of the hoses or intercooler....you would have to have someone on the throttle holding it to boost pressure while you listen to where its coming from.
Hi Mike....welcome to the Forum
If you would like to draft up an advert to post in the For Sale section then I think it will get seen and hopefully a buyer found.
Any rough idea of how much he would want for it?
Cheers, Trevor