Are there any pitfalls I need to be aware of in installing a complete new system (new HU, door speakers, rear deck speakers, sub and amps, and rear door if I can figure out how to wire them)? I've got the keys to take the head unit out - well they're on the way and the antenna adaptor. I heard there was a power block I can tap into to power my amp's, is that true and where exactly is it? And what is the best location to run the RCA cables and speaker wires? I know I've asked a lot of questions - sorry, I'm anxious to get started!

Your car isnt all that different as far as where to run wires..<ul><li><a href="http://www.audiworld.com/tech/elec82-1.shtml">A4 Stereo Upgrade</a></li></ul>

Thanks Adam. that helps, although I don't think I will be going to all the work you did. Great installation! Do you need to take power off the battery, or can I get it off of the power block under the dash as I saw suggested?(I'm speaking about power for the amps in the trunk.)
If not, what about running them under the car and up through the floor of the trunk?

...it is PREFERRED to go straight to the battery, and put an inline fuse within 18 inches of the battery.

Do not run the power wires under the car.

Just go directly to the battery and install a fuse within 18" of the battery.

Okay, I'll run it off the battery and through the car. This is going to be a job, I can see it coming.
Will I be able to bypass the OEM amps if I wire seperately to my amps and then tie into the speaker wire running to the doors directly? And yes I am replacing the door speakers.

Run your new wiring from your amps all the way to the speakers. That will make it much simpler. If you're worried about trying to get wires through the rubber boot into the door don't worry. The boot is big enough to run new wires into without much trouble.

run it off the battery. takes about 30 min to do the work and is the best way of doing it.

to familiarize yourself with the concepts and best practices.

Thank you HIS4. I appreciate it! So I should just be able to grab the power, ground and constant on out of the factory wiring harness once I remove the OEM radio? Are there any other things I will need out of it?

You might want to look for the illumination wire if you want your head unit to dim at night. Make sure the K-line is not hard wired to +12V otherwise you won't be able to use VAG-COM on your car, and make sure you install the right antenna adapter. The adapter should have a lead on it that you hook up to the power antenna lead on your new head unit.

The illumination wire and the K-line are easily identified in the OEM harness by looking at the diagram on top of the OEM head unit.

I got the antenna adaptor, however I haven't tried it yet. I don't remember another lead on it for a power antenna. I'll need to take a look at it - the Metra 40-VW10 is what I think I got.

you need a 40-VW54 which has the power lead connector.

Thank you 5speed6. I appreciate your help. Now I have to find one of those. There are none listed on eBay at this time.

<ul><li><a href="http://www.installer.com/antenna/">Click</a></li></ul>

Thank you 5speed6...