that's exactly what you're doing... putting in 5 or 6" subs with some separate highs... just make sure there's an amp behind em, otherwise you won't hear its full sounding, peak potential.

 

So will an amp add more thump to my car?

I was planning to get a sub an amp at the same time but I might get the amp and then later on the sub.

 

yeah.. it'll increase some bass with the mid's and high's, of course.. you gotta get a box with a sub or two if you want thick bass though.

 

putting an amp to the speakers will increase overall output it will increase bass but will also increase mid and high so your bass gain over other gain wont be noticeable It will allow you to play louder and still maintain good sound though and if/when you add subs I would highly recomend an amp to the rest of the speakers to ballance them out. JL all the way baby

 

yeah, this guys got it right on the button as far as side speakers are concerned. you'll be able to get the music a lot louder while still keeping your SQ (sound quality). see, there's only so much a speaker can do without some sort of enclosure (box). so if i'm correct, judging by your word "thump", i think you want some sort of speaker inside a box in your trunk. the door panels aren't gonna cut it and give you the "thump" you want --> only to some extent, but you can't shove a 12" woofer into your door, of course.

 

Just something else to think about smaller subs are more efficient have a better sound range and usually are more crisp and accurate than larger subs of the same class. I personally prefer 10's to pretty much anything (I use 3 10" JL's). I haven't tried it but I hear that 4 8" subs works good too.