We're probably going to be picking up a 2011 GT coupe this weekend if we can make the deal happen at the dealer. I've been looking into what I need to buy to get the stereo up to my standards.

I've decided on a JL Audio stealthbox, Alpine PDX-V9, and probably MB Quart separates on plates. What I'm not sure on is the sound processor/LOC. I've installed some pretty high end systems in the past, but always with an aftermarket head unit. This car has factory nav that I want to keep. I'm not entirely sure where to tap the speaker level signal at. Other threads say to tap it off the back of the radio before it goes to the shaker amps, but is the nav system hooked up like this too? With other cars that had amps, I was able to unplug them and jump around the speaker wires. Is this what people are doing in the Mustang? Finally, what about the factory subs in the doors? Are they worth trying to keep working?

My final dilemma is whether something like a JL Audio cleansweep is necessary or if you get good sound with just an LOC like the Audiocontrol LC6i.

Sorry for all the questions. This is just so different from anything I've done before.