I've found KBS Stiff to be almost the same as PX6.5. The Stiff plus or Xstiff is about the same stiffness specification wise as the PX7.0, but KBS is much more soft feeling than either DG or PX.
I agree it shouldn't matter, though.
Shouldn't matter too much if you don't take full swings with it other than buried bunker lies?
Usually, people go with stiffer on wedges, but I guess it doesn't really matter as much because most of the time you don't even take a full swing with wedges anyway.
I don't know what his choice of car had to do with his behavior, but if he had a problem with you,, there is no excuse to be rude to your daughter. I know if I was playing with a golf pro, I would welcome any help with rules. Some people feel rules and etiquette don't apply to them. This seems to apply on and off the course.