I relation to my threads on here about general BOSE weirdness and lack of control over the Audiopilot and EQ settings i got a reply from BOSE support. Good news about the Audiopilot settings, not so good news about the rear speakers and EQ.

"We as Bose do not recommend eliminating the noise compensation technology
AudioPilot. But if you feel sound turning down more disturbing than comfortable your
dealer can turn off the AudioPilot function by following changes of the amplifier
pinout connections:
Your dealer must connect pin 24 with pin 6 with a bridge in the harness. In this
case pin 24 is pulled to 12 V if the amplifier is on. (The GPIO input of the
amplifier is configured as an AudioPilot on/off switch, so with this bridge your
dealer turns off AudioPilot in the software.)

Concerning the setting possibilities in your Audi A3 with the Bose system you have
only the possibility of making subsequent changes by using the controls given by
your radio (bass/treble/facer/balance/etc.) No EQ or Pan settings are given in
conjunction with the Bose system. Normally we recommend to set all radio controls to
the normal, zero or detent position. Bose sound systems are engineered to perform
well at detent, providing more degrees of variability to accommodate personal tastes
and quality of different sources (e. g. radio, CD, cassette, etc.).

Fading to the back will not reproduce strong sound in the rear speakers. The system
layout is focused on the front seats. But if you have set the fader to the normal
respectively zero or detent position, you should enjoy life-like and spacious sound.
Naturally we are conscious that there are straight quite different expectations with
such a subjective topic as good sound. "