I got the subwoofer already like that. It would've cost more to buy a box and the subwoofers separately and install them. Altogether, it's a $630 stereo system. I thought about getting a power capacitor, and still thinking about it. But my headlights don't dim at all. I also chose bandpass because they are the most efficiant type of subs out there. I just want it to use as little of power as possible and still sound good.