Use RCA cables from the head unit to the amp, you will produce much better quality sound that way. Capacitors are used to take the load off of the alternator/battery of the car when the amp draws a large load when listening at a loud volume. It's just a filter to keep the voltage consistent. The stock wiring is great, but you need to find out how the car is wired before getting into this, it's not like any other car. The speaker wires all junction in the trunk, where the amp should be located if you have one (driver's side behind the carpet on the side) There are wires running from the amp to the head unit area, and sets running to each individual speaker (on my '93 525i at least). I had to find out what wires were coming from the head unit, and cut them off the harness to splice them into the speaker wires. There are wiring diagrams on www.bmwe34.net, and
http://bmwe34m5.com/articles/E34_91_535_wiring.zip
unzip it and read the text file to find the acrobat file regarding radio wiring.
PS: If you use RCA cables and an external amp for the speakers, you dont have to worry about the stock wiring behind the head unit, only finding power for the head unit.
Last edited by bimmerd00d; 03-08-2005 at 05:21 PM.
1995 540iA M-Sport - 76k miles. 1 of 1 auto AW3 cars.
1995 540i/6 - Misc Parts donor for above.