Mant moons ago, I was the tech man for the shady sideshow of "Stock Car Racing" that operated at Bryar Motorsports Park. Basically, the term "Stock" has so many definitions and modifiers, and so many pitfalls in enforcement, that pit road lawyers everywhere perk up when they hear it - and guys like me cringe
"Unprepared" has worked fairly well for us, for the last 40+ years - I don't beleive it's the part of this that needs fixing.
And while I'm ranting - I see little need for bring our classes into "alignment" with other orginisations, who are behind us in dealing with many of the issues involved, and not doing all that hot with a bunch of others - you know how many classes in SCCA will kick you out for having too good a rollcage?