Moin, I have an A6 4B with Bose System and a Kenwood retrofit radio. The LS VL, VR and HR have given me some really funny sounds for some time. After 24 years I had to expect the HR to be released already 2 months ago because it has only knattert. I ordered now 4x Ground Zero GZTK 165 3 Ohm and (perhaps only 2) DIN adapters to connect. I just changed the two front ones. First of all I noticed that VR installs an ESX Quantum 16cm 4 Ohm was, left original Bose. After the exchange the sound quality was better, but the bass was almost gone. Do they just need recording time or did I do something wrong? I can’t polarize it, because I have installed extra matching plug&play adapters (tomzz Audio 7103-003-2) from Amazon. At the radio settings I didn’t change anything at first. Does anyone have tips?