I just finished installing the Kicker sub in my 2020 AT4 with Bose system. I also added the Kicker CXARC control. I played around with the Kicker Amp's dip switches and decided the factory setting is good enough (1 up, 2-3 down, 4-6 up). I have my Bass EQ set to 0 on the head unit and the CXARC set in the middle. One thing to note when installing is you do not need to cut the floor mat around the sub (if I need to pull it out I will just loosen the sub box mounts and remove). I tested the sub with Dire Straits - Money for Nothing (CD on USB drive), some other Artists/Songs and Sat radio and it integrates perfectly. Setting the Bass EQ to 0 removed all most of the bass from the found doors which really make a difference.
Also on the factory under rear seat storage you have to remove, I am going to cut mine to fit up to the sub box (left side) for the right side and edge with plastic trim you can find on Amazon (need 1/16" I believe). I will cut a template from cardboard so to get a good fit when I cut it.