Right, you have a couple of options,

1: get the correct retrofit loom from the dealer, a one that has DSP, nav and phone, it should be plug and play then.

2: try and adapt the loom you have by adding the phone and nav to the DSP (not easy).

It's not something I've done myself, but I have thought of retrofitting the DSP to my e46, so have looked into the pinouts.

Do you get any sound at all for what you have now? if so what works and what does not.

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Sept 03, M3, Silver Grey. Retro-fits: Modded Mk4 DVD Drive, OEM Bluetooth, VR Control, Rainbow Speaker Upgrade, Sony SOT Amp, HK Sub, CCFL, Intravee II, NightMode.