Hello! I am new here. Just got my new 2016 audi a7
I have the stock Bose System and would like to install my own bass system in there.

I've done it before in my old car but not sure where to start with the A7 as it already has an amp at the back for the bose system. In my old car I also connected the output to come from the rear speakers as I didnt want to go all the way to the front panel and wanted everything to look stock from the outside.

Once I get the box mounted and the amp on the box, I assume there is a battery at the back I can connect to for the Positive and the ground on the Negative, but where do I connect the output to?

I've searched for tutorials but only found 2 quick and to the point installations but it didn't answer my question specifically.

Thank you for all the replies in advance!