6 pt bar on street car

I'm a rally tech inspector and I always advise people to be very careful in putting bars in cars that see street use. Your head(s) will go all sorts of places that you would never imagine in an accident, and it does not take much of a fender bender for your head to end up in the bar. I know one guy with a plate in his skull from this. (And this does not count possibly broken bones....)

For family use, I would strongly advise against it, even though I know that some may get all riled up at this position. The reality of what can and has happened should guide everyone to see the very real possibilities of cracked skulls. Weight added, experiences on the track, and whether it impedes entering or exiting have absolutely nothing to do with this aspect of what the OP is concerned about. This issue should be a separate decision point that can nix a bar on the street by itself. Make your own choice as to the risk that you find acceptable PLUS considering the very high cost of the consequences if it turns out badly.

The OP is very smart in asking this question. I would advise that you look at this as completely separate decision to make, and not put it into a mix of tradeoffs with the other factors.