Harnesses - are an
absolute must for any well installed system, most are full Plug & Play and will allow 100% reversal to stock condition:
If you're the adventurous type and want to tap in or make your own custom harness:
DIY: Amp Wiring Guide (for HiFi and L7 systems) or
Wiring Diagrams for the Members
Where is the remote wire?
e90 HiFi Upgrade - with some DIY wiring info (pg 1-3) and running wire to front doors (pg. 4)
An unrelated thread with s
ome random useful OEM wiring parts/connectors
.