Metra Dash Kit Prep - The most time consuming step during the installation is getting the Metra dash kit to match the factory trim. The Metra kit is delivered with a glossy, textured finish. As you know, the trim in the C6 is matte/satin black and is perfectly smooth. To get the factory finish, I sanded down the Metra kits face plate with 600 then 1500 grit sandpaper until it had a smooth finish. At this point I sprayed it with a Krylon matte finish which can be purchased anywhere that carries Krylon. It is just a clear finish that takes the gloss out of paint. The other option is to have the face plate bead blasted instead of using Krylon matte. Whichever method you use, you will still need to sand down the face plate. Remember, if you mess up, the dash kit is only around $10.

Below is a factory picture compared to the Metra kit after preparation:

DNX8120 Prep - In addition to spraying a matte finish on the sanded Metra kit, I also sprayed the trim on the DNX8120 itself since it comes with a smooth glossy black finish. Not wanting all of the logos and part numbers that come on an aftermarket head units trim, I removed the trim plate from the radio (5 tiny screws, 3 on the top and 2 on the sides) and sprayed the left, right, and top borders with Krylon black gloss and then Krylon matte clear. I don't like the Kenwood logo on the bottom border but it would be a nightmare trying to spray a black paint in that area since it contains an LED lenses and buttons that cannot be removed before spraying. It is satin however so it's not that bad.

Below is the faceplate before and after:.

If you don't know how to solder, learn! It's a must if you want quality connections.

The DNX8120 comes with a lot of outputs and inputs on the back. If you're only replacing the head unit and not using a rear camera, you will not use the cables with RCA connectors, only the standard speaker wiring.

Now is a good time to solder and shrink wrap the GMAH24B, GHAHCM, and PAC SWI-JACK to the the head unit wiring. I'm not going to go over this in detail since the instructions that come with the adapters and DNX8120 are detailed but I will try to cover the highlights. Since wire colors are standardized, it's just a matter of color matching

Parking Sensor - If you want to play DVD's and enter NAV information while driving, you can simply ground this wire. This is not considered safe and is probably not lawful but if you want full functionality while driving, running it to a ground is all you need to do.

Grounding - For all wires that require a ground, make it easy on yourself and solder them together and then connect them (solder) to a single 10 gauge wire and run it down to a bolt on the amp under the passenger floorboard where the fuses are. I have no radio hiss using this grounding location.

Grounding Location:

Dimmer Wire - In order for the dimmer on the DNX8120 to function properly, you must supply a signal to the dimmer wire that connects to the radio. Do not solder the dimmer wire to the GMAH24B, it will not work. Instead, splice into the grey wire on the traction control button. This button only lights up when the night lamps are turned on and will tell the head unit to dim. Again, run the dimmer wire directly from the DNX8210 to the traction control [grey] wire.

Reverse Wire - If you're not using a camera, you can just trim this back on the DNX8120 harness. In the future I may mount a camera on the front of the car to avoid hitting curbs with the splitter (haven't yet). The DNX8120 does allow you to manually turn on the camera which would be necessary with a front mount install.

PAC SWI-JACK (If you have steering controls) - This module needs switched power. I simply spliced into the switched wire on the relay (87) that's attached to the GMAH24B. You will not need most of the wires on this unit either. The instructions (you must get car specific instructions on their website) are clear on the wires to trim back. You can also trim and tape the mini-jack wire which the instructions do not mention. Program this device and test thoroughly before you put the dash back together. I programmed the 1-6 button on the steering as a mute button. I found this much more useful than the factory programming.

GHAHCM - This module needs switched power. I simply spliced into the switched wire on the relay (87) that's attached to the GMAH24B.

Accessory Ports - If you want to control your NPP exhaust (like I did) or any other relay activated device, connect this wire and run it down to the fuse box area for later connection. If you don't have NPP or any other device, do not install this harness into the DNX8120.

GMAH24B - The instructions with this adapter state that if you have the premium Bose 7 speaker system that you do not connect the rear speakers. This confused me so I connected them anyway. While everything works and sounds great, I have later found out that the system might actually sound even better with the rears disconnected. I would suggest doing before and after tests before you button everything up.

GPS Antenna - You can mount this under the dash but on top of the two middle A/C vents. Reception is great in this location!

Bluetooth Microphone - In keeping with a factory look, I mounted the microphone out of sight, on the lower left hand side of the console as in the picture below.

This is a simple procedure. There are two screws under the emergency brake boot (remove the boot, it snaps out) and two in the console compartment itself. You will also need to remove the shift knob. After the screws and shift knob is removed, you can start gently working the console out. Don't forget to disconnect the wiring while you are pulling it out.

Here are the guts: