With those codes the only assumption you can make is the engine is junk and you're buying a roller. So if the rest of the car is in otherwise good shape and you feel like buying a replacement engine, the alternative is to expect to part out. Take what the seller says as only marginally accurate.
Below is interesting reading and is a similar if not exact problem that is still ongoing.
http://986forum.com/forums/general-discussions/63007-aos-question.html