So I had somebody PM me about the quality of the GB10D4 subwoofer. I use it in a 2013 Jetta in my spare tire well. Here's my unfinished false floor install...
This sub is a beast. I have it in ~.5 cubic feet sealed in my spare tire well crossed zt 70hz w/24db slope. It's matched with MS-A5001. It's been measured to be ~850 watts output at 2ohm. So I got out my radio shack meter and tested "fast" response as well as "slow" response. The results are from the "slow" metered response. I can't tell you how amazing it sounds in the car matched with my ms-8.
I was able to hit 112 decibels C-weighed on avicii - hey brother. I was hitting 118 decibels on awolnation - sail. I didn't max out the volume. I had my kid in the Car and it was getting too loud. I was hitting 123 decibels on bassnectar - bass head. My kid went inside but I still didn't max the volume because I started to worry about my neighbors. The amps and speakers didn't show any signs of breaking a sweat.
I checked A-weighted too and on fast response I was easily getting mid one hundred-teens.
This is sealed, inverted in about .5 cubic feet. Wow.
The bass is well...bass. It's very immersive and clean with a punch(thanks mid-bass). Everybody that's heard it play is wow'd with how clean it is in addition to it's overall presence without bringing ANY attention to the rear of the vehicle.
My son(age 3) picked the music...except bassnectar. He loves playing DJ whenever we go out for errands. Here's the songs, streamed through youtube and playback via bluetooth
EDIT: Fixed my crazy phone input issues. Also, I've only been playing this for a little over a week on 30 minute commutes to and from work...a few hours sprinkled in here and there enjoying the install