See my post below. All my measurements assume a 1-3/8" to 1-1/2" spacer.
I'm hung up on efficiency now and pumping as much power I can into the midbass because I may need to stick with the factory amp for a while until I can raise the cheese (money) for a fancier solution. The factory midbasses are highly efficient 2 ohm drivers. If I want to keep the system balanced I'll need a similar driver that hopefully has a higher excursion.
Right now bass is really holding this system back. It booms at 60hz and sounds muddy and sloppy. It's an obvious target to tackle.
Ge0