I know the point of a 4 point harness, I don't know the point of a harness bar. Also the way that thin steel bar is done is just like the subie/evo bar and in an acciden the two bolts lower to the belt snap, the bar rotates on the other two where the seat belts were and the occupant goes flying out the windshield. Has happened several times on and off the track on other cars.
Also I should note that 4 point harnesses are stupid and you will be F'd up if you crash, you need to have an anti submarine belt when using rigid mounted shoulder belts.
Throwing this in for some info
http://www.ogracing.com/blog/2013/02...ing-harnesses/