Audio Design Wheel Well Sub Box w/ amp+sub | 2015+ S550 Mustang Forum (GT, EcoBoost, GT350, GT500, Bullitt, Mach 1) - Mustang6G.com
LaVoce SAF184.03 18" Professional Subwoofer Driver – GSG Audio Design
1x Gravity 8 Inch 1200 Watt Car Audio Subwoofer w/ 4 Ohm DVC Power 8' Sub Single - Feature Dual Voice Coil, Thick Magnet, Design for Car, ATV, Van, High Performance Car Show : Electronics
How to Design Your Own DIY Subwoofer - TurboFuture