E60 Base Stereo Upgrade questions

[adrian67]

Hi there!
I’m texting you from France. I have some questions,

I want to upgrade my EU VERSION 6 speakers Base Stereo with M-ASK which is really bad SQ by 2x cf4032s Infinity for the high front channel (driven by the HU) and 2x Logic7 underseats woofers driven by an Aftermarket Amplifier (Focal Auditor RIP 4280).
I know that I have to code to HIFI my M-ASK by adding $676 to the VO. When done, there’ll be 2 low-level diff balanced channels output available (+L, -L, +R, -R), I’ve planned to tap the wires to the aftermarket Amp by splicing a 16ft RCA.

I’ve seen on Rockford website that I can tap from the back HU like that: + (pos) to the RCA tip, and the outer RCA grounded to the head unit chassis for both side (Left and Right) which means that I leave the -ve (negative) not working.

https://www.rockfordfosgate.com/rfte..._inputs-pa.pdf

Tell me if I’m right. I’m still looking to other solutions. My last thing I’d do is to get a Bal/Unbal converter... Here in France it’s very hard to find and expensive.

Thanks everyone!