I have a 2014 wagon manual and was out having fun with it. While under my fourth or fifth hard acceleration I had an extremely loud pop (like a baseball hitting the car). It sounded like it came from about the rear seat area. I received no warnings or cautionary lights. I drove the car home under lighter loads but tried to isolate it but can't and the car drove fine. The car has about 3200 miles and no mods. Any ideas before I take it to a dealer?