I found these 2 empty connectors in my boot (one in the right side, 1 in the left) they are identical. What are they for?

Left side:



Right side (where CD changer etc sits):



I don't have DSP and BMW confirm that my car never came with DSP - are these connectors for some kind of BMW plug&play amp/sub or something similar?

Also, I have the Motorola V50 kit in the car - can any other phone or kit be attached in its place?