This is the tune I've been using of late. I find it works well at moderately high volumes. At lower volumes (such as when you have a passenger and are having a conversation), this tune benefits from 1 or 2 clicks of fade towards the rear. For me, this seems to tone down some of the harshness of the hk tweeters at the expense of some of the perceived width of the stage.
The base was BimmerTech's issued harmon kardon tune of 2/15/16.
- All frequencies on the right sub were increased 2 units in the AF software.
- Both left and right front channels had all frequencies from 125 to 4000 increased by 2 units
- Both left and right front channels had all frequencies from 5000 and up decreased by 2 units
- The center front channel had all frequencies from 125 to 2000 increased by 2 units
- The center front channel had all frequencies from 5000 and up decreased by 5 units
EDIT: I also muted the center channel with the software.