I did state that the human ear would probably not detect. The speaker will. However, it does pull more off of the electrical system of the car. If it didn't, then there would be no need to bridge. May be a small amount more due to running high-end, but more. Hey, it's someone else's system, so it really doesn't concern me.
I wouldn't run mine that way. 'Tis all I was meaning to say. I am not a fan of four-channel car audio amps anyway. So, what ever will be, will be.
There is one thing for certain when asking more than one person for help, you get more than one opinion.
The most important thing in car audio is being sure the cars electrical system can handle the complete load. Replacing the current battery with an Optima battery is far from what it takes to provide good power to a system. In this type of situation, I am standing firm to my recommendation.
Just for the sake of this thread, annunaki is far more educated in audio than I am. So I am not here to battle, just give to my opinion. And in this situation, as I stated, it's firm.