I just bought my 2013 PIU about two weeks ago. The guy I bought it from had only owned it about 4 weeks when he put it up for sale. I was leery about buying it because he was offing it so quick but his story was his wife hated it after he bought it for her. Absolutely hated it. My wife loved it. It is what she wanted and was local enough we went and looked at it. I was given the VIN prior to looking at it and the Carfax I pulled showed regular maintenance and no wrecks / air bag deployments. So far so good. The seller also had paperwork from a Ford dealer supposedly giving it a clean bill of health which he shared with me. He did casually mention it needed a exhaust gasket replacement. I could hear the putter of a leak but it had no other issues so after a test drive we bought it. It made the hour long drive home no problem and runs great. Nice and tight with NO rattles showing 127,000 miles.
I have noticed a bit of a exhaust smell when turning on the heater / defroster. Coupled with the noise of a leak I sent it to a shop for a look see. One manifold gasket was leaking where we could see and the other was missing a stud and there was soot on the side of the block so both were leaking. After pulling the front manifold and replacing the gasket and bolts / studs the rear one was pulled and the gasket was fine. The manifold was cracked on the bottom side from heat. The reinstalled front one was pulled back off for a closer look and it too was cracked! The manifold / catalytic converter is all one piece and I imagine they get extremely hot, especially if a unit has a lot of idling time. New manifolds were ordered from Ford. There are 4 (!) oxygen sensors on these manifolds and the top ones are almost as expensive as the manifolds! The bottom ones are about 1/2 the price of the tops. This has turned out to be a very expensive repair on a vehicle we just bought! If you are looking at a PIU and you hear a exhaust leak be advised it could be very costly.