Bit the bullet and got the Stealthbox. Replaced my 10" dual voice coil Bazooka with this. Was hoping for a little more low end frequency extension. This definitely has that! I asked what the low end went to - by way of calling the JL rep. He said "Something like 28HZ". The Bazooka is specified at 39HZ for low end response. I actually had to change the EQ settings on the AVIC-8000 a bit. I was overcompensating by bringing the 50HZ lowest band all the way up (to try and squeeze more low end out of the Bazooka). Now, I have it pretty even with the last three lower frequency bands. All the bass notes from 120 down to 30HZ range sound fairly even and linear to my ears. I am pushing the Stealthbox with an Alpine MRV-M500. The gain was fine where it was with the Bazooka sub. The bass has a MUCH stronger presence and sounds really clean. Lower notes shake the seats and you feel it in your chest. That was EXACTLY what I was looking for.
There is no lack anywhere in the bass spectrum now!
Caution: If you roll the windows down, the bass just gets ridiculous at that point. It feels like you are effectively sitting in a bandpass box!
Highly recommend a remote gain control for your amp.
The enclosure is supplied with a bracket system that would require the woofers be pulled, holes be cut in the mat and the interface bracket be attached to the vehicle frame. Decided to just wedge box in place for now with some materials I had. The carpet is a very close match to the interior (see pictures). I am rather picky about stuff like that.
Conclusion: It IS a lot of money, BUT the sound is awesome. It really lacks for nothing in terms of quality bass reproduction, IMO. Typically, I'm not a big fan of sealed enclosures, but this seems to have the best qualities of ported and sealed. The look of the box is very appealing to me and looks like an OEM part. Am very happy with it!