Mine had the factory 4 speaker for a while. I upgraded radio and I mounted amps/sub and a set of 4" separates up front with tweeters on the A-pillar. It sounded really good IMO. My back speakers died years later and I put in a better pair of JL Audio coax that were much more efficient than the prior ones (eclipse). It totally changed the sound stage and not in a good way. Louder definitely, still clear at that louder point, yup, but the sound stage and a lot of the highs now sounded like they were behind my head. It was like going to a concert and sitting backwards. I removed them and put others back in that didn't have the tweeter. I then replaced the fronts with JL's still with separate tweeter mounted low on A-pillar and loved it. The only part that would have made it better would be if I had changed the mounting and gone 5.25" like suggested.
As for the "I have 2 500w 6x9's in my rear deck xD
Just need to get an amp, not enough power out of my little pioneer to really move them" you have much to learn in the audio arena. Your gettin' ripped off. You could have some 1000W ones for $42!!!
http://www.sonicelectronix.com/item_...s-HFI69CX.html but you might want expand the true knowledge base some and read up here to start
http://www.crutchfield.com/learn/lea.../speakers.html
Many of the seriously expensive, audiophile speakers like this (
http://www.edesignaudio.com/product_...roducts_id=508) only handle 100W RMS (160 peak) and the guys drive them with max 150W. These are the guys doing audio competitions for sound quality. Sorry to say but what you got is the flashy advertising to make somebody who doesn't know think they got stuff that's better than sliced bread or indoor plumbing. Now getting a lot of power to proper subs in proper boxes will make big changes but it depends on what you are looking for, ground shaking 2 block away bass, or great range concert hall detail and clarity.
I can tell you that with quality stuff with 50-60 watts on each channel and a nice sub powered accordingly, you can make yourself deaf really quick.