As of right now you can't change the intensity of the B&O lights.
But you can see them (very faintly), there's a little LED on the lower part of
the corner speaker (if you turn on the B&O light) and look from below upwards to the lower
part of the door tweeter you'll see it, the other light is in the center speaker and it is very faintly
visible when it's open (you probably can best see it from the outside when it's dark)
There's an official bulletin by BMW to let dealers know about the B&O lights and given the wording
there could be the chance of new/additional settings at some point (introduced via new sw updates)
Below is a picture of the backside of the tweeter with the LED light/lead
