had a problem with sts kit today on a drive
The turbo uses rings to seal the bearings. If oil pressure builds up in the turbine, it pushes past the rings and into the exhaust/intake. The fact that your oil buzzer went off means that you lost pessure to the pump (which scavenges oil from the turbine). Thus, the turbine overloaded and dumped the excess oil. Turbo should still be fine

What you need to do is disconnect the intake side pipes and clean the oil out from them. It'll blow onto your MAF otherwise and cause the car to run poorly. Also turn the key to the "run" position w/out turning the car on and make sure you can hear the oil pump cycle. If not, check the relays under hood (the 2x black boxes). If the relays get wet (which happens often as the stock harness lays by the front spring perch), they won't work properly. Good news is they're easy to find at most major auto parts stores and are cheap
Also check the connections on top of the oil pump under the car. The spade connectors will sometimes work loose causing intermittent voltage. Finally, if you still have the resistor in the system (the gold colored one under hood that gets stupid hot), cut it out and reconnect the wires. The resistor runs the pump at low speed when not in boost = less oil scavenging from the turbine. The pump will run fine in high-speed mode all the time.BTW, my STS after 2+ years of operation did the same thing, cept' I didn't have the buzzer sound. I spoke w/ Mike at Va Speed today to get an oil restrictor (to decrese the volume of oil pumped into the turbine) + a small sump under the turbo before the oil return. It'll be a week or 2, but will let you know how it turns out.
Good luck.....sorting out the oil return is the main problem with the system



