Chop: Might be a dumb question but are the Infinity's replacing your 4 main stock one's in your VX??

I getting ready to upgrade my Pioneer head unit and the China(ebay) motorized monitor for an all-in-one Pioneer model AVH-P4900DVD touch screen also a Pioneer CD-IB100II iPod ADAPTER and a so-so Kenwood powered sub and I still have the stock speakers and will need to upgrade...I'm not after a crazy loud system just a nice comfy sound..