Okay, so I have decided not to go the component/amp route and instead just get some nice replacement speakers for the front and back, as well as either the Kenwood DPX-501 or DPX-701 head unit (I am sold on getting a double din to fill out the dash nicely).

I am looking for front speakers in the $150 - $200 range and rear speakers up to $100 or so (but I'm flexible).

Although I realize you will not get incredible bass out of a coaxial speaker, I need the best bass I can get from these, since I will not be adding a subwoofer.

In perusing the internet, I have seen models from Alpine, Infinity, and MB Quart that have peaked my interest. I know they are all reputable brands, but just don't know enough to know which ones would be the best choice.

I was thinking it might be a good idea to get a crisp speaker with upper frequencies for the front doors (something like a freq response of 72Hz to 30,000) and then speakers with better bass response in the rears (something like 35Hz to 20,000). Is this reasonable logic at all?

Any suggestions? I would particularly be interested in responses from people who have done a simple speaker/head unit swap like I am planning.

 

I hear only good things about Polk Momo and Alpine Type-R

 

Yeah the Alpine SPR-57LP is another one I was interested in. Nice frequency response of 35-30KHz.
http://www.hookedontronics.com/show_...lpine_SPR-57LP

I am not interested in loudness, merely sound quality, so am I correct in paying a lot of attention to the frequency response of these speakers?

 

I have Alpine S-type 5x7s in my '06. I chose the S-type over R-type because the Stype has a directional tweeter and a higher sensitivity rating. Off the top of my head the Rtype was 88 or 89dB and the Stype is 92 I believe. So the Stypes are more efficient which is a good thing, especally if you are running them off of the deck amp. The other speaker i would throw into the mix is the infinity reference or kappas. they are very nice for the new model year, and right in your price range. Good luck and happy listening!
-Dean