Conclusion: In my 22 years of dealing with Car Audio, these are the best subs i have ever used hands down!!! This is also an excellent price because when i bought my first pair back in 2006 i paid $325 per speaker!
Summary: I put two of these in my four door Silverado behind my back seat in a custom built ported box and they fit perfect. I have them on a 2800 watt amp with the kenwood indash and they just sound amazing. It catches almost every bass super clear. Defiantly got my money's worth.
Conclusion: I have two of these subs in a down-firing box under the rear seat in a GMC Sierra Crew Cab. The bass is tight, and these speakers produce lower frequencies amazingly well considering how relatively inexpensive they are. I have a RF Prime 1200-1D powering these amps wired at 2 ohms.
Summary: Put 2 of these in my 2012 F-150 supercab. I figured with them being slim, they would be weak....HOLY CRAP!!! They pound hard!! I can't even turn the bass up all the way on my system. I am only running a 1000w kenwood amp and it handles it fine.
Summary: I have two of these in a ported box in my superduty powered by a kenwood x1200m amp with a cap. They hit insanely hard and the sound quality is amazing. I am yet to hear or feel anything close shallow mount or otherwise.
Pros: hit hard and sound quality, they don't make noise, they make bass you feel in the chest