Because it's $700.00. I can get my sub, the two door speakers, & amp cheaper than buying the stealth box.
But you still need a box, and someone to build it, that's going to cost cash. They've also tuned the Stealthbox for the Mustang.
How much cheaper is the sub you're getting?
2012 Mustang GT Premium (Manual), Sterling Gray, Brembo Package, 3.73 gears, Electronics Package, Comfort Package, HIDs, backup camera, Koni Yellows, Steeda Sport springs, Steeda HD mounts, UMI panhard bar, Borla S-Type catbacks, MGW shifter, Driveshaft Shop carbon fiber driveshaft, RTR wheels, Michelin Pilot Super Sports, Roush front fascia, DG Custom hidden fog billet grille, Roush lower billet grille, Roush front and side splitters, DG Custom quarter window louvers, GT500 rear diffuser