According to SCCA personnel:
All roll bars must be braced in a manner to prevent movement in a fore-and-aft direction with the brace attached within the top one-third of the roll hoop, and at an angle of at least thirty degrees from vertical. It is strongly recommended that two such braces be used, parallel to the sides of the car, and placed at the outer extremities of the roll bar hoop. Such braces should extend to the rear whenever possible.
As described, Ben’s roll bar does not comply. We have been researching this for some time and have yet to find a roll bar for a Mazda MX-5 that is compliant. We suggest that Ben get a factory hard top. 
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So naturally, I wrote back a lengthy email explaining how GoodWin cars compete all the time with these bars. I even included very detailed installation pictures of three different options that GoodWin claimed were perfectly suited to track use (Quick Change, Double Hoop w/Quick change (which has additional weld in plates), and as a last resort, the Petty Bar option (which requires cutting up your carpet).
Response was something about
"pursuant to code blah blah blah" the weld plates shown only had 2 bolts instead of 3 and that the SCCA actually prefers to see a sandwhiched plate design with 3 bolts... which for all practical purposes is impossible without removing gas tank, whole rear end, etc...
They pretty much just told me to forget it and get a hardtop (mega $$$ and pretty effin rare to find used)
WoW! That track indeed looks quite torched... Esp in the turns, which obviously is where you'd want the smoothest pavement. Why in the world wouldnt they just resurface the turns ???