Hi fecat
If you like the look of the twin hoop bars have a look at the MX5 plus twin hoop roll bars, I have been in a roll over and it happened because we were T boned so it can happen in any car, I just put one of the twin hoop MX 5 plus bars in my NB8B and they are great...!!! I looked at the BD bars as well but was more impressed with the MX5 plus bars and the way they mount and the position of the support arms.
The guys that designed them are engineers, and have these bars in their cars and their kids cars, so they feel pretty secure with them, as do I. From memory the bar I have will take about 9 tonne for and aft and about 3 tonne downward pressure before it bends, hope fully I'll never test it.
I have seen a few photo's of rolled 5s and not on the track, and did a lot of research before I bought the bar I did, and for me its a no brainer, roll bar or nothing and these bars look just as good as a style bar anyway.
My has a mod plate so no problems with the law.
Roof works fine
No problem with visibility at all
And I can still put the roof up from the drivers seat.
The wind deflector goes( working on a new one to fit between hoops)
Good luck with your decision
Regards
Old Dude