only way to know for sure if it is turbo seals, is to run the car and see if the tail pipes are blowing smoke. Give the car the good old power brake and have someone hold a white rag or paper towel to the tail pipes and see if oil shoots out, or a black heavy soot. Also, take out a couple of the plugs and see if they are getting on the dark side if oil is burning. Chances are, the turbo most likely has a bad seal.
Also try and see if the shaft on the turbo has any movement what so ever. If you can pull it in and out at all, or move it up and down, then it is definately time for a new one, or a refurb. A simple rebuild and your stock turbo will be as good as new. Turbonetics are a decent bunch of guys who rebuild our turbos for a good price, and if you want to upgrade, now would be the best time.
Hope that helps!!!
John