You can play around with the DSP tuning to make ASD reasonable. The default BimmerTech tune makes ASD unbearably loud. I'm using a slightly modified version of "Marshalltj _Aug 3 _Revised_TUNE_BSW_LHD" and I feel the ASD is only slightly louder than the base HiFi amp and still very reasonable. (I modified it so the center channel is only getting input from the front channels and I turned down the level slightly)
If you have the time, try all the different settings people posted and tweak your favorite one as needed.
ASD audio level isn't controlled by the head unit's volume control. So a quick way to tell if the ASD is going to be too loud is if you have to turn down the volume for your music compared to the original HiFi amp.
http://f30.bimmerpost.com/forums/sho...mmertech+audio