[Bob D.]

The dash speakers are not crossed over, nor are the rear door.
The front door speakers are crossed over at the head unit or the speaker, that's why they sound muffled by themselves.
The Infinity amps rating is closer to true RMS than most aftermarket amps.
Wattage per driver-- divide by six?
Technical information on the Infinity system is pretty sparse. Using an audio analyzer would be the only way to get real info.
Good luck getting info from Infinity.