2003 Ford Explorer Sport speaker replacement

I am planning on replacing the (horrible) stock speakers found in my
Explorer Sport (2 dr model). I have the standard stereo with only 4
speakers ( at least I can only see four speaker grilles in my SUV) and
no sub-woofer in the trunk. Does anyone know what size speakers are in
the front and the back? I've been searching for owner's manuals and I
can't find any online help about what the speaker sizes are. And if
you're wondering, I'm trying to replace the horrific stock speakers
with either high-end 2way or 3way speakers