Your subs may not be "broken in" - however I think it depends on which input you are using. My iPod, for example, plays louder than my satellite, which is a bit quieter than the radio. i didn't have the factory system in for long enough to break it in, but I agree that it was pretty week as far as car audio goes. I guess I'm a bit biased because I always had subs in my old one. My brother's '10 G37 has a pretty banging system for a factory system, however. You actually need to turn the bass down for it to sound normal... Maybe you should double check the wiring on your unit?