I drive a 2004 Buick Century. I recently put in 2 5.25" kicker DSC50 in the front (door panels), and 2 kicker dsc6903 in the back (rear deck). I am going to install bass blockers on the fronts becasue I listen to a lot of rap and the fronts are just being punished by trying to put out so much low frequency (also putting in dynamat around front speakers because of problems with them being in the cheap door panel). I am thinking about adding a subwoofer, and I do not know what kind I would need, what power would be necessary, etc. The 6X9's are very good with bass, which makes me question if I really do need one, but my other question is wether to add an amplifier or not. The rear Kickers (6x9) have an RMS of 90, while my head unit can push 55Wx4 RMS, which is great for a head unit alone I think, but it is less than the rear speakers could take in theory. So should I use an amp to push the rear speakers to their full potential, and while I'm at it should I add a sub? I know I would need a 2-channel amp for that (sub+ pair of speakers), but that is about all I know. I also was considering a powered sub to avoid needing to install a separate amplifier and save some money, I was looking at bass tubes for example. Would it be smart to do a 1-channel amp for the rear speakers and then a powered sub in addition? The 6x9's really do punch hard, which makes me wonder how much power I would even need from a sub... I know I am very clueless, so please help me!! I need you guys!