Nice install Bruno. I'm (hopefully) about to buy an 1998 E36 M3 (subject to a dealer inspection tomorrow).

You mention a few times using the factory speaker wiring from the head unit to the amp instead of new cabling which others used and had noise problems. Did you have any noise issues?

AFAIK, the normal BMW headunit outputs a balanced signal which means you can use twisted pair wiring no problem. However the empeg is single-ended. So reusing the wiring is technically the wrong thing to do particularly when the amp at the other end is single ended as well - yours isn't it seems so your lucky. As you are using a differential input amp like the factory one you'd probably get away with it. I've seen at least one other E36 install done like this (empeg too link here), but he used the factory amp.

I don't really want to do such an extensive install on my future car, but I'm going to need MP3s somewhere or somehow. I was hoping for perhaps empeg only and leaving the existing amp and speakers. I know BMW is not renowned for the stereo systems though so I might just do the head unit first.

I want to keep mine fairly reversable too in case I sell the car.

Thanks for the info - there really isn't that much out there that I have seen.