can I create an AUX-in with the stock radio/cd changer

You can purchase a product from PIE called the SON-AUX and splice it into the CD changer cable. This product will give you an Aux input, I have the wiring info if you are interested.

I've used it to hook up my ipod to the system, externally everything remains stock and the sound is perfect!

Thats what I was looking for too. Does this look like the one you instaled?
http://www.discountcarstereo.com/detail.aspx?ID=572

Exactly!

Add this cable http://www.discountcarstereo.com/detail.aspx?ID=1015 and you've got it. Perfect sound; no FM Mod hiss, excellent dynamic range, and you still maintain both the stock appearance and the CD changer in the back.

Thanks for the info. Did you install it yourself? How did you run the cable from the trunk to the console area for your i-pod.
I would just get a new sterio w/ aux input but I dont have a garage and cars get broken into all the time around here just for a sterio. I need a stealth system otherwise a survellance camera and a baseball bat.

A bit of both, actually. I removed the center dash unit ( comp, stereo, climate ) as well as the center console ( lighter, storage bin ). Excellent opportunity to clean all the little bits and replace all of the bulbs...

I had the installer wire the SON-AUX unit in behind the center dash console with the ipod cable hidden in the storage bin next to the parking brake handle. The splice on the CD changer cable was done approx. 8" from the head unit connector. Power for both the SON-AUX and the ipod charging cable was drawn from the cig lighter and grounded to the frame directly.

Reassembled, it is impossible to see anything. Even the ipod is hidden when laying on the bottom of the storage bin.

Two bonus features:

1) I added a Scosche RF remote for the car

http://www.scosche.com/scosche…egoryID=127&ItemID=IPNRFC

Didn't bother to attach to the steering wheel, prefer to just hold it while driving. So I don't even have to ever touch the actual ipod.

2) Hid the video output end of the cable in the seam near the passenger's left leg, that way you can plug it into a portable LCD screen. Ipod video movies over the car audio system for those long drives!

I planned to make a proper instruction set and post it here, but I was so excited that I had to get the info out now! Proper instructions forthcoming!

SON-AUX Description:

The SON-AUX allows you to add an Auxiliary Audio source to any radio while still being able to maintain your CD changer. The SON-AUX is a current sensing device that will automatically interrupt the Audio lines going to the radio (and switch in an external RCA signal) whenever audio signal is detected on its RCA inputs. The Audio lines will reconnect to their previous state 10 seconds after no audio signal is detected by the SON-AUX on its RCA inputs.

The SON-AUX allows the connection of an Auxiliary RCA source (Walkman, iPod, portable DVD, VCR, Satellite radio tuners, MP3 Players) to the radio while still being able to maintain your CD changer.

You said, "The splice on the CD changer cable was done approx. 8" from the head unit connector"

Do you know what color wires to splice the RCA's into? I could do it myself if I knew what wires.

Doing it yourself should be no problem; here is the pinout and connection.

The main cable is shielded and the audio cables are shielded as well. For future flexibility splice female RCA plugs to the line, rather than the SON-AUX directly.

As far as I know, there is no module made specifically for the E31. If there is I would like to know who makes it...

Did you get the video cable as well? I just plugged a friends portable DVD player in and watched Entourage on his screen and the sound booming on the cars speakers!

Hope this helps, I'll try and place a proper procedure soon...