i will try one more time. a harness and a roll bar in a street car is dangerous for all the reasons i already stated numerous times. street conditions are an unknown, anything can happen, objects, other cars, pedestrians etc. tracks aren't perfect but they have alot less unknowns.
in a street car:
roll bar and harness=dangerous, no movement incase of FRONTAL roof cave in
roll bar and stock seatbelt=more safe than above, movement incase of FRONTAL roof cave in, EXTRA upper protection
harness bar and harness=VERY dangerous, no movement no upper protection
i hope this explains what i mean, i don't know how to be anymore clear than this. i would use your setup "oc civic" autoxing but on the street i would not use the takata's, i would just stick with the oem seatbelts.
edit: your rollbar is ONLY dangerous if your head were to hit. it's the harness combined with it on the streets that is the problem.