This installation was on a 2000 Ford F350 pickup. The rear seat was removed to access under the seat to install 3 amplifiers and a power cap. We install two Interfire 10" subwoofers in a custom box. We also relocated the electric rear window motor to give us more room for the . Three amplifiers used in this system were also made by Interfire. One amp powered the subs, another powered the inside speaker. The last amp is set up to power an additional box for when you are tailgating or are at the beach. A 1 farad power cap supplys the power to all 3 amps. A large 150amp fuse and holder were used for the system Crystal connects Kool series rca were used for the low level signal. Three Pac high to low convertor were used from the factory radio to the rcas. We used Micros 8gauge power and ground cable and two micro distibution blocks.