As for street racing I shall refrain from commenting.

Roll cages and/or bars in street cars though, not every car is necessarily safer by putting a roll bar in it.

For example I thought it'd be all nice and spiffy looking to put a double-hoop chrome rollbar in my Miata. But the only place to put it is right behind the seats and it wouldn't be that hard to smack my head on the bar.

So for a Miata you're supposed to put the proper padding on the bar, but then you don't have them pretty chrome hoops up there, and it just looks freaking ugly.

If I were to have some sort of high-powered car that is capable of running in the 10s and also driving on the street, I wouldn't want to put a cage in it. Door bars are no fun going to a nice restaurant or something. I wouldn't necessarily run it on the highway. I would be more inclined to show up at a track, make one pass and get kicked out because it's too quick, and not have that cage.