Nox sensor has been lately in PITA in these, they have been changed at Goodwill in Europe, I guess its same in USA because you have much better deals with all warranties overall.
Oil cooler seals are better than early models but they still can fail, never heard oil pan leaks so far... I would ask them to show what is the fault code behind EML.
Transmission oils should have been changed around 40000 miles (It is 60000km in Europe service). Get them changed if not done. And personally I would like to get test drive feeling how car changes gears. Solid transmission is changing very smoothly, problematic one hits gears at low gears especially when cold.
Then some general points to watch out (not to to freak you out but for information, many owners never face these problems, and I bet gasoline engines have their own problems if going this detailed level too):
Timing chain DO stretch (earliset at 80000 miles and onwards). If oil filler hole is front of the engine, it can be easily checked, but they moved oil filler mid of teh engine at some point. Usually stretched chain has not caused disaters but timing could be off several degrees and you may hear rattle on cold start. Mid priced repair.
Exhaust manifold brittle. No way of checking beforehand. Pretty rear failure but usually turbo goes at same occasion. Expensive.
Turbo drops oil on swirl flap motor and motor fails. Not expensive but takes time.
Turbo actuator fails. Not expensive.
Injector bottom seals fails ---> 'black death'. Not expensive but takes time.
Not engine related :
EIS servo motor fails, steering lock won't open. Expensive repair if go locked and dealer changes whole EIS. Can be repaired when symptoms starts, by changing only motor (15 bugs) but some labor time. Not a problem if gear selector in steering rack.
