Make it structurally sound, using SCCA-approved gauge tubing, and use the seatbelt mounting points for your mount points. If you design it well, it'd be an optional weld-in or bolt in.
You can put a disclaimer on the product all you want, like every other roll bar mfg'r out there. Keep it around $400-$500 and I think you'll pick up some sales.
Bear in mind the rear 2 points will need to be adjustable in length to accomodate Gen 1 / Gen 2 positions. I had to fab 2 extender brackets to go from the Gen 2 to the Gen 1 on my Rickety bar.
Wish list - optional removeable door braces for more of a 6-point setup. It might not be competition-legal, but for those who do serious track day participation, it'll be safer than not having them. Oh, and include the single / dual shoulder harness mounting tabs too.
You'll also want to discuss this with the Administrator of the Forum, as Group Buys / Sales Ads need to be paid for & approved, especially with some of the recent issues with some of them.
Locking until the admin sees it.