This is an underseat enclosure I built for a Chevy Pickup. These are custom made. I can likely make one like this for your pickup as well.

This enclosure was sealed and housed two shallow Phoenix Gold subwoofers along with a Stinger 5ch amp. We added a few nice details like the recessed subwoofer so we wouldn't need to use a speaker grill. LED lights throughout the enclosure as well which was a nice touch. Rounded stack fabbed corners custom made to fit the curve of the seat. And also a mixture of carpet and vinyl materials and lots of layers to add some detail and depth to the enclosure cosmetically. 

I can make one similar to this for your vehicle, with or without the details listed. As with all custom work, price will vary depending on your exact enclosure and options. Please contact me for a quote!