Put a JL Audio 8" ported sub under my rear seat with a 200 watt amp. Easiest way I found was to just use a line out converter. I am very pleased with the end result compared to the alternatives and the sound quality is pretty good for an 8". I used a JL amp running 200 amps. If anyone has more questions or comments let me know.

 

Very nice. I wonder if that sub would fit and sound good in the factory sub box.

 

I'm not sure what the factory box is but this is under the back seat of a super cab (extended cab) and the box is a JL box that came with the sub... It's a pretty shallow unit though so I'm sure it may fit in the factory box.

 

great choice, im running two jl w1v2 10s love jl audio best in my opinion