A roll bar does two unrelated things: protect you in the event of a rollover and stiffen the body. On a convertible, which has lost its roof and a significant amount of rigidity, the difference is noticeable from the first bump - less vibration in the windscreen and a front axle that stays aligned with the rear.

These are styling and stiffening roll bars, designed for road use and open track days. Timed competition under a license requires a roll bar approved by the governing federation, along with its certification sheet: this is not the same part.