Ok, so I've been looking into a subwoofer for a while now but I just don't really feel like spending $600+ for a sub, amp, and new head unit, while leaving the other speakers as factory non-bose speakers. The sub I had picked out was Pioneer's TS-SW2501S2 or S4. I was going to do an install of it in the compartment area in the floor in the trunk so it was hidden. It said it had a frequency range of 20Hz-290Hz. But, now that I've looked at other regular door speakers I've noticed that Pioneer also sells 6.5" speakers that have a frequency range of around 30Hz-30kHz (models: TS-A1604C,TS-G1643R, TS-G671M, and TS-A1684R). I was wondering, since the frequency range is so low for these, would they hit the lows like a subwoofer would, but without a huge kick? or is there more to it than that? and also, if I go with any of these, would I need to upgrade the factory amp or install a new one? I'm looking for a more fuller sound from the speakers when turned up. When I turn the bass up to +6 with the factory speakers, the bass hits almost hard enough for me, but it fades in and out when the sound is up. I'm looking for something with a little more kick and better performance. I hope this is enough info for someone to answer. Oh yeah, I have a 2003 TB LT with non-bose, forgot to add this earlier.