I just recently purchased a single 12" vented Fox Box. I couldn't be happier. I have a Rockford Fosgate Power T750/1 driving an Alpine R-Series 12. I like all kinds of music...basically everything but some of the newer hop hop. SQ is excellent, and if you want it to, it will get very low and loud! It is perfect for my taste. I've auditioned just about everything music wise, and have found no flaws with the sub or box. I would definitely purchase another one if need be. I recommend the vented enclosure over the sealed. Fox Acoustics was easy to deal with and they shipped the box six days after I ordered online. The box arrived 24 hours after it shipped.
I have an acquaintance that had a custom enclosure built for a single ported 12 in the exact same vehicle. He is driving it with a JL RD900/5. My sub, in this box, ran off of the Rockford Power 750/1 sounds significantly better than his set up, and his sounds nice. Of course, I have twice the power, so that helps. He also spent close to $900 just for the enclosure. Dollar for dollar, I don't see how you could beat the Fox Box. On top of everything, it looks really nice. I think it set me back $150 shipped. Again...I couldn't be happier.
Pics at the link...
https://www.ramforumz.com/#/topics/262073