Found this thing. It's flat, and surely it's better than no subwoofer at all...
Buy 8'' 600W Under Seat Car Active Sub Woofer Speaker Stereo Bass Audio Powered Amp: Component Subwoofers - Amazon.com ✓ FREE DELIVERY possible on eligible purchases
www.amazon.com
Don't waste you money on that. There's no branding of any kind, which means its a knockoff of a Chinese knockoff. I'd be worried about the truck burning down. If you really want a cheap slim packaged sub, look at something a little nicer, just don't expect a lot from them.
A friend has this NVX one in his beater truck (90s Nissan reg cab) and it does alright as long as you don't try to push it beyond its capabilities. Rest of the system is an old Kappa greencone 5" component set hooked to a 35w x 4 amp. Basically built from leftovers, but sounds better than most newer systems.
Amazon.com: NVX QBUS8P 300W Peak (150W RMS) Amplified and Loaded 8" Ported Under Seat Quick Bass Universal Subwoofer System with Remote Bass Knob : Electronics
www.amazon.com
