Sounds like you bought a toasted engine, get it checkout by a mechanic at the expense of the guy who sold it to you

 

My turbo went out about 8 months ago at 120k miles. I posted here and on Audiworld that I needed one. Someone on Audiworld contacted me and sold me a low miles stock turbo for $150.00. It is a sound turbo that has worked perfectly.

 

Here's some on eBay

http://cgi.ebay.com/ebaymotors/vw-au...QQcmdZViewItem

http://cgi.ebay.com/ebaymotors/Vw-tu...QQcmdZViewItem

http://cgi.ebay.com/ebaymotors/Audi-...QQcmdZViewItem

The one that I bought had no shaft play.