Honda Civic Forum : “Upgrading 2007 honda civic lx sedan sound system?”

Upgrading 2007 honda civic lx sedan sound system?

I have a 2007 civic lx sedan with the basic 4 speaker stereo system. The sound is only decent and not that great. I was wondering if I replace the stock speakers with replacement speakers but do not touch the receiver, or bother to put in an amp or sub will I notice a noticeable difference? I was looking to replace them with these speakers which have great review, but do not want to start messing with the car and adding everything else. http://www.crutchfield.com/S-LiOhBBLuwqk/cgi-bin/ProdView.asp?g=400&I=107DB650

Thanks