It does make a difference what type of music you are playing and even what song you are listening to with the system completely stock. The stock subs have a very very limited range of audio playback, limited even more by the stock head unit. Even with my aftermarket head unit and modified amp wiring (seperated front and rear inputs) there are just some songs that the subs sound like they arent doing anything. They just are too small for the low stuff but are limited by a crossover to keep vocal ranges from being played by them.