NASA uses Chassis Dyno specs so they use a HP to WT ratio, HSR uses a Tech inspector and Cu In class, not sure how they verify though. A lot of people run both series so I'm sure there's a lot of honor system involved. It is a hobby league of sorts. You can get suspended for making contact in those series. Pushing the envelope is one thing but over aggressive driving is frowned upon.
SCCA Historical series gets fanatical with proper date codes, car pedigree and such, I don't think I want to play in their sand box. They frown on newcomers and reproduced race cars.
Wanting a Custom fit in an off the rack world.
I don't have time for a job, I just need the money.