Completed the install! :fighting0030: It was so involved and time consuming that I didn't take images of the process as I intended.
For the feint of heart and those who aren't terribly mechanically inclined (like myself) go ahead and pay a professional to do the install. These cars are built like little tanks. I've done a couple of basic stereo installs on other cars and can usually get them done in 1 day.
It took about 12 hours over the period of 2 days (with 2 people) to complete what should be a simple Amp wiring and install.
The time consuming parts:
Car dis-assembly (take your time and be patient)
Power Wire through the firewall/dash (definitely need a coat hangar and having 2 people helps)
Running the wires (to be expected)
We were able to get everything installed very cleanly and professionally. I soldered all wires and jacked in behind the head unit (I used the front R/L channels).
The little rockford mono amp (pbr 300x1 I believe) doesn't want to run high level off the back of the head unit (from my basic testing). However I did also run the remote wire to the cigarette lighter under the dash which works perfectly.
Back to the original thread topic - The
Uber Stealth under floor box. As everyone else has stated it is a very well made box and performs admirably in our little cars.
I paired it with a pioneer 10" 2-ohm sub and a tiny little 300w Rockford Fosgate mono amp. I also loosely packed in some poly-fill. I have the gain turned all the way down (wired a remote adjustment at the dash to manipulate levles) and I set the crossover to 120 hz.
This combination fills out the lower end of the stock system perfectly. The sub definitely puts out some volume and can overpower the stock speakers quite easily.
edit #1:
After a couple hours of higher volume listening the sub seems to be breaking in nicely. The sub is hitting quite well with a decent amount of punch for a single 10" woofer. The base is tight, fast, and clean. There is a peak in the base response around the 60 - 80 hz area (guestimating) - EDIT #3: After a few weeks this "peak" area I noticed initially has leveled out and the output seems quite uniform across the entire range. I'm not having any issues with the sub reaching the upper ranges ~120 hz and it seems to reach the lower ranges quite well (~30 hz).
Even though the sound quality and the base levels are great in the cabin of the car ....... I do have a sinking suspicion that a good deal of the "rattle your pants" factor is missing due to the fact that the sub is firing upwards. I highly doubt the side mounted enclosures address this factor.
My bottom line at this point: I'm very happy with the enclosure and the impact a single 10" sub has on the over-all sound quality of the "stock" sound system in my '09 GTI.
edit #2:
I forgot to mention that I made a major blunder during the install.
After everything was installed I hooked up the battery to test that the system was working. I did this before putting the seats or dash back in.
Putting the key in the ignition and turning the key to the "on" position resulted in
MAJOR FAULT CODES!!!!
IMPORTANT!
Never ever have parts of your dash or the front seats out of the car and connect the battery/use the key. It will result in Air bag fault codes that can only be cleared with vag-com or by a dealer/shop.
Couple of quick snapshots:
