Welcome to the forum. Uhh... where to start...
If you're going to have the speakers professionally installed, is there a reason you wouldn't have the installer also source the speakers? If going that route, I would just have the installer work up an itemized estimate and then have the installer price match the hardware with Crutchfield.
Backing up a little further... what are you trying to do, exactly? Get more volume? Better sound? I got a long way with a quality head unit, sub amp & subwoofer.