I am interested in buying a used 2013 Q7 TDI Premium Plus with low miles 30K. I have not test driven the car yet and I was wondering what should I be looking for at this SUV as far as the engine, underneath, interior or anything? The car was previously owned in California. Any known issues with this year model? I did my research and I could not find any issues. It is out of the warranty and I don't know if the diesel fix has been done yet. To those of you that got the fix what changes have you noticed on how it runs, gas mileage or anything different in general?