It was a custom file. The Mountune is aggressive in some regards, but lazy in others. It hits super hard down low and always broke the tires loose in 2nd, even when it was warm. Like I would be driving around on the Strat tune, holds second fine. Load up Mountune for fun, and tire spin lol. Also, first gear was DEAD. You either had 20 hp or all 200. Very frustrating to drive. Stock was more enjoyable around town. All that being said, the Mountune is still the fastest for sure on my car.