I have a paid of Rockford Fosgate FRC4306 Reviews

Worth replacing the stock speakers with, or more hassle than its worth?

 

I'm not sure if you'd hear much of a difference... the rockford speakers probably are not as sensitive as your stock speakers and need more power to run than your stock ones.

It might be a bit more clear, but not as loud. Your speakers are only going to be as good as the source that the sound comes from... in this case your deck. If you have the stock head unit it wouldn't make too much of a diff... maybe a bit cleaner at nominal volumes, and a tad bit more bass at higher volumes. I'd swap out the deck along with upgrading the speakers at the same time.

Or run an amplifier off the stock head unit and use a good hi to low level converter like the MTX RE-Q or Peripheral s4ven.

 

Right now the only head unit I have I could throw in would be a Pioneer 45x4 DEH-1450. Not sure if that would be better, if at all...