I too own a 2013 Mustang. Mine is a V6 Premium with Pony Package. My summer car. If you like the vehicle, tell the dealer you will purchase it 2nd to a pre-purchase inspection. It was the best $250 I ever spent. I won mine since 2018 and it has been a dream. No issues at all but then I do not drive the car daily. My daily driver currently is a 2023 Subaru Outback Touring XT. i do show the car during show season and it has won awards.
