I recently purchased some new audio components for my 2008 Subaru Impreza and intend to install them myself this weekend. I was just looking for some guidance and tips on what I'll need to complete this task. Here's what I'm installing:

-Pioneer DIN head unit (this should fit perfectly without a harness by the looks)
-1200W RMS Amplifier
-3500W (1000W RMS) Pioneer 12" Subwoofer (I'll have to make sure not to over power with the amp)
-Sealed box for the subwoofer (I've been told to go ported but I was looking for better sound quality and trying to save some space)
-I have a package that includes the following:
1. 17 ft. of 4 Gauge blue power cable
2. 3 ft. 4 Gauge black ground cable
3. 17 ft. Neon blue series RCA cable
4. 16 ft. of Speaker wire
5. 17 ft. of 18 Gauge blue remote turn-on wire
6. 6 ft. of Split loom tubing
7. 1 AGU Fuse Holder
8. 60 AGU Fuse
9. All Necessary Hardware for Installation

I will be putting the subwoofer and amp in my trunk. So some general aspects I'm looking for help with are as follows:

-What cables will I need to complete the installation?
-Where is the best/easiest place to conceal the cables?
-What adjustments will I need to make to the amp so I don't over power the subwoofer?
-I want to avoid damaging my car as much as possible so, how should I mount the amp and secure the subwoofer?
-Anything else you can think of