If you're like most people, you spend more time listening to music in your car than any other place. Too bad most car stereos have weak sound quality, especially in the bass department.
Adding a subwoofer is the single, most significant improvement you can make to a car audio system. Not only do you get the benefit of the subwoofer's superior bass performance, but with proper system design, you also relieve the small front and rear speakers in your car from the burden of reproducing bass. This makes them sound better, cleaner and louder.