As the title says, I want a small (I consider) upgrade to my audio. I like the quality of sound I hear from the speakers for the most part but what I want to do is add some kick to my bass. I feel like the amount of bass I have sounds cheap and stockish. I don't want people next to me at a red light with my windows all the way up to be able to hear every word of my music, I just want the rumble. What do I need and about how much would it cost to have a decent set up for what I'm looking for? I don't want to blow anything, put it that way.