congrats on the purchase..
, Sounds like you found a creampuff.
I'd start by changing ALL the fluid...oil, trans, and rearend. Next, depending if its a E99 or L99..(L99 has "diesel" badge on the door), if L99, i'd change the coolant to an ELC, so you dont have to maintain SCA's. E99, well ur stuck with either the gold or green stuff, maintaining the sca levels.
I'd then, clean the engine bay up good, covering the power steering cap and alternator, dowse the engine with simple green, let soak, then "lightly" pressure wash it clean. From there, you can make a DIY boost leak detector..(google's ur friend) on how to go about it, spraying ur cac boots with soapy water, then pressurizing the system...any leaks, fix ASAP.
Then, take a look behind the turbo at the uppipe collector. Any visible sign of soot either there or on the firewall, well, you have a leak at the collector..gotta fix that too
From there, if oil / fuel, present in the "valley" of the motor, gotta find the culprit..mainly the drain valve on the fuel bowl and/or turbo pedestal leaking from the EBPV rod..(riffraff has a "cabinet kit" for all these orings).