Originally Posted By: ARCOgraphite
... If you've got POWER ( 75-150wRMS 20-100hz , 0.1%THD) - go air suspension, closed box.
I agree with this portion of the above comment. Lots of RMS power, sealed box. IMO most people don't need anything bigger than a 10", unless the feeling of the vibration is what you're after. As for brand, just don't go with cheap junk from the big box store and you should be fine. Fans of "elite" gear will snicker, but I always had success with mid-level MTX subs. If I had more money to spend in my car audio days, I probably would have gone with Soundstream. The sound from the local Soundstream demo vehicle was very convincing.