I would imagine that unless you have pre outs of some kind, you are gonna have to splice into your rear speakers, somewhere. Then depending if your amp has high level inputs or not, you may or may not have to use a line in converter. If you follow the instructions over at mustangworld, that should give you some kind of idea, the only difference is where you get your input from. I just installed 2 12's on my mach system, it wasn't too bad. Try to find out how to remove your rear speakers, and try to splice into the wires. your signal to the amp might fade though, because as you increase the volume, your radio backs off some bass. The answers are out there, just search. If I can help anymore pm me. There are some good guys over at mustang exhaust also. Sometimes I get a faster answer there. Good luck