TIGER RACING
In scca GT2 you can really press the issue. Barry Schoenberger's GT2 Tiger started as a pile of tubular steel and blueprints. The only Rootes piece on the body is the rear cowl section, the rest is fiberglass. Once it was described as a minature Trans Am car. It goes like stink.
Tom Patton's GT2 championship winning Tiger isn't a tube frame car like Barry's. It gets a weight break. The tub of the body was once a Rootes product, but both front and rear clips are now tube framed.
At big historic races like Laguna Seca, the cars must have a documented racing history.
Many years ago I began preparing my MK1A and my driver credentials for what later became the Chicago Historic races, when the cars just had to be period correct and look good.