My god! Your still running the standard front speakers, I threw those out as soon as I got my car home after buying it!!!!!
The standard fronts are 13cm, its easy to replace them with co-axials, you just wip the old ones out, cut off the connector and replace them with some spade connectors and away you go. If you go for separate components it gats a bit more complicated. You cant just run some new speaker cable through the rubber tube that runs between the car and the door, because theres a connector on the end of it which limits the way you position the speakers.
The fronts will make a big difference to the sound, but only if you balance the sound properly with the 6x9s or else theyll just take over. To be honest with you, I originally had co-axials in the front of mine and 6x9s in the shelf, once I got a sub it screwed the overall sound up big time, so I got rid of the 6x9s all together and it made a big difference in the overall sound quality.
Rick