Guys, I'm not denying your 15's are "tight". I have always been under the impression that the eclipse I heard in a sealed box was tight. It sounded fine to me..until I heard something much, much better.
I suppose it's kind of surprising that "better" happens to be a stock system in a pickup truck. But once I heard it, I realized the big bulky 12's and 15's are just...sloppy.
12" RE SE, 1.8 cuft box net, ported and tuned to 32 Hz. Receiving 750 watts. "Sloppy" in comparison.
Gains set by ear, verified with digital multimeter. I don't know what else to consider as far as "install".