I read a lot of threads and the E34 site to discover I might loose some fuctionnality (balance, fade) if I only change the stock head unit. And some cracking noises and such... Which I got after plugging all the wires per diagrams including all negative speaker wires. After trying without any negatives as suggested, that didn't do much except for faint sound 'til playing with the fade and balance.

Then I plugged in the negative right rear since nothing was coming out of it all the time almost... Amazing sound comes from my right rear speaker at last... sound also from the front that was there. But the left rear is a little deaf... so I plug in the left rear negative and BINGO !!! SUPER SOUND HEAVEN !!! (Well, I'm so frikkin' happy that's how I see it).

ALL WORKS ! Balance left to right, fade front to rear ! AND POWER ! No cracking noises whatsoever, no problems any !

YYEAAAHHH !!! I'M THE MAN !!! I'M THE MAN !!!

Now I've got to figure how to put the radio anteanna in. Splice ? Adaptor ?