system advice pls

[BigWill]

so i just bought a 2005 GMC canyon crewcab 4x4, and i want to put a sub in it... so heres the issue
THERE IS NO F***ING ROOM FOR ANYTHING!!!
i would like to keep at least room for 4 people in the truck
not looking for a huge system, but just a little more bass to make the shitty stock stereo sound better
if anyone knows what i could do, or if anyone has done anything like this in there canyon or colorado, please give advise, or suggestions.

[BigWill]

does anyone on beyond make custom sub boxes?

[ca18det240sx]

is the rear seat a bench?

[97'Scort]

You can get a slim sub under the seats no problem. The new JL slimlines only need a 0.63 cubic foot box.

[hoamic11]

pm wrxer1, he does custom jobs

[Jonathan@TCS]

MTX Thunderform has one that drops right in. I believe it goes under the rear seats. You can get them without an amp, or with an amp built it, which would save even more space. Check them out at MTX.com. You can enter your vehicle, and it will show you pictures of it in the vehicle.