on my '12 vert, the amp for the front 8" subs is located behind the drivers side kick panel. i have seen wiring diagrams on here. the 8" door subs are dual voice coils so there are four sets of wires in that harness. the factory amp output is in the gray wiring harness. In order for me to get full range inputs I used a JL audio summing line convertor.
2012 GT CS Ingot Silver Vert, Edelbrock E-force supercharger with CAI and 3.5 Pulley, Tremec T-56 Mag, Accufab 84.5, Centerforce DF, Billet Yoke aluminum driveshaft, FRPP 3.73 Rear, MRT Performance H-pipe, Bassani axle backs, JL Audio sound, Edelbrock strut tower brace, JPC adjustable UCA, UMI adjustable panhard bar, KW V3 coilovers, Steeda heavy duty front mounts, Steeda rear LCA's, 20" Steeda Spyders with Michelin Pilot Super Sports, Steeda Big Brake Kit ....... it just keeps going.