C8 -
We're a longggggggg way off from shipping to other states. That's a big deal with alcohol sales. Someday...
Are you saying you're 34 years old, or more like 46? My hearing starting dropping out in my mid-30's. I'm guessing your's will eventually succumb to all that abuse. Unless you're one of those folks who has thick, gross earwax plugging everything up all the time, givng you natural protection.
I have to take a little issue with your discussion of 2 subs instead of 1. The primary improvement will be because of the two locations and bass volume increase, not the reasons you list. Bass may not be very directional, but when you are in close quarters with lots of sound-absorbing materials, you can tell where it's coming from, and 2 sub drivers can help.
When you run one subwoofer, it's always out of phase.
No, it's not.
At higher, neighbor-bashing volumes, it wouldn't make that much difference. But at lower volumes, the difference would be dramatic.
That argument implies that biasing the low-end (through an equalizer or preferably separate sub amp) would eliminate the "problem" of only 1 sub. While I think biasing will take care of most shortcomings, I agree with you that 2 subs sound better than 1. But at low volumes in cramped quarters, I believe it is the directionality and simple increase in bass volume that makes the difference, not any magic caused by the 2 subs "interacting" with one another.
In general, I don't think the extra cost of a 2nd sub for a standard auto configuration is worth it, but it makes more sense for a pickup truck (if you can find room under the gun rack, above the Skoal chest, and behind the Willie Nelson CD's).
Scronch