The car would have to be absolutely perfect for that price, and I don't mean look perfect, I mean check out perfectly.

Other than the obvious stuff that a used car inspection would include, I would check the transmission adaptation values for signs of imminent trouble (this can be a real life-saver). I'd also look at the "smooth engine running" values as well. This will tell you if the car will need plugs/wires (not cheap even if DYI) in the near future. You can also look at the fuel trim data. This can give you an idea of how long the MAF sensor is going to last, or other possible issues. You can even check to see if the engine is an oil burner by checking the record of "engine oil replenishments".

These are just a few of the things i check when performing a PPI for a potential buyer. Of course, you'll need an SDS, or equivalent to check all this stuff, but it's worth it. I could fill volumes with horror stories I've seen myself.