Nopi just needs to look at IA model. $10 per car, and i bet those guys are making $10-20k per event easy. Strip it down. This isnt 99-2001.
Smaller classes, smaller prizes, people just want an excuse to hang out and see something different. They arent trying to win car shows and crap like 10 years ago. Racers want structured competitive classes. The race cars will benefit from the payouts and that will draw them in way more than the "car show" people. The car show people will show up if you provide them a place to park for them and their friends.
Vendor booths, my advice is due the BARE MINIMUM to cover expenses. Unlike NOPI Nationals, you are not going to get money for the vendor booths. Companies have downsized, gone under, etc. You want to advertise that "FORGED PERFORMANCE IS bRINGING AN LFA" and hope that draws in 10000 people rather than try to make money off Forged. the "DOOR" is where you make your money.
Since no one really trusts or cares about Nopi anymore, your goal should be to throw a cheap show that gets everyone to show up and yearn for the next one, then you can think about charging vendors more, etc.
My advice is pack as many vendors in as possible, that will attract people to pay your cheap DOOR price, break even, make a small profit, throw a great show, then gradually increase the vendor prices next show when you have something to show them and you have proved yourself.
Right now, the old NOPI name, means more negative than anything