Z3 Roadster 3.0 2002 head unit aftermarket swap.

[BLUEBETTSYE28]

Hey guyz, I'm planning to change my OEM head unit to a Kenwood Excellon KDC-x300. Main purpose is to get aux and USB which the OEM doesn't have.
I will have the necessary wire harness to make an easy swap. I've already replaced all the speakers (except door tweeters) with new mid grade ones. My question to anyone who has done this; will I loose use of my subwoofer powered by the factory amp or will this harness link everything. Please reply with your experiences and ideas. Thanks for any info.

[MarcoZandrini]

The thing to remember is that the factory amp uses balanced differential inputs. These signals are of a higher voltage than line level/RCA signals. That is, balanced diff signals are typically a volt or more (peak to peak) while line level/RCA signals are around 1/2 a volt (peak to peak).