HELP: Impulsivly bought 2005 a6 Quattro W/ Blown Engine
 

So after perussing craigstlist for a few hours I found a 2005 A6 Clean title for $2500 with a blown engine. The cherry was the seller had a full engine he was including with 90K on it! I decided on a whim to purchase her. She's a 2005 3.2 Quattro and every-time it turns on briefly; the engine + tailpipes and underbelly spit out oil. I had it towed to a shop of mine but any ideas on where to look first? I am hoping the previous owner didn't hide something from me and I wasted money but I hope the Audi Forums Community can shed some light on this.

For Background: This is my 3rd A6, (First two were totaled in an accident). I love these cars, I hope I didn't just throw away $2000!

Sincerely, The Newbie Audi Enthusiast

TLDR: Bought a high mileage A6 on a whim. The seller threw in an engine and now I'm worried I got a major pain in the butt. Any ideas where to start looking first for major problems? Thanks!