At 80k miles I'd be more worried about the PTU and water pump than a Turbo failure. I've have both fail at less than 53k miles, and a whole lot of other things - but no Turbo problems yet.
If there are no records available from the Seller you might consider paying for a CarFax yourself to see what history the car has, like: location (rust), accidents, maintenance, etc. Or, if you know a mechanic, have them give it a look, fluids, brakes, suspension - the usual culprits.
Good luck!