Stock Speakers in 05 M&T??

[jscherf92]

Im looking to replace the stock speakers in my vibe and i know they are 2 ohm speakers and a 2 ohm amp, and ive read that hooking up 4 ohm speakers would result in a 3dB loss but if i replace the head unit would the change be that big of a difference?Anyone have specs on any of the stock stereo equiptment? So far i only know that pontiac claims it as a 320w system with a 100w 6.75" Subwoofer.