I had a MTX Thunderform for my Dodge Truck. It sounded pretty good for what it was. I added a few layers of sound damping within the enclosure, and that helped the sound a bit. The enclosure would "flex" a bit in places.

It stayed in my truck for about a month before I changed to a different pre-made enclosure. That stayed for about 2 months.

Finally, I built my own enclosure, which has been in the truck for 3 years. I have changed subs a few times since then, but the enclosure is the same.

Just my experience....