Use that diagram and run 4 new strands of speaker wire from the radio to where the factory amp is now. The twisted set of wires are the pairs that go to each speaker (right front, left rear, etc.) This will bypass your factory amp and allow the radios power to run everything.
The nice thing about most BMW amps is that they power everything individually. In the future you might want to run your tweets off of a small amp, and the mids off of another amp and the wires are all there to do so. Its soooo nice, real versatile. Hope this helps...
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