i have one with bar one caged
doesnt take much in the way of mods to be fast enough to need a roll bar (11.50), bolt on a ta-49 and you can be there
my local track follows the rules , faster than 11.50 and you wont be running anymore without a roll bar , run 9 anything or over 135 and it roll cage and comp license time or no racing for you .....so either turn it down , dont go to the track or comply with the rules
the bolted in rear seat bar isnt legal , some tracks dont allow it some dont get that picky
and the shoulder belts have to attach individually to the rear bar and in such in way that they cant slide , a welded tab or tabs is perfered , if you do wrap around the rear bar you have to have a way to keep the belts from sliding
and the sub belt must be 3" and through bolted and washered through the floor and belt can run around the front of the seat
you dont need to have the passenger door bar for a roll bar to 10.0 , just driverside per rules but most install the passenger side anyway if for nothing else but to stiffen things up