Mean, what you said is the rule of thumb at local events. If you get protested, someone usually asks you what you have done to your car and you tell them and they might say that you class was wrong and fix it so that you are in the appropriate classes.

When thousands of dollars in contingency money is on the line, everyone is not such a nice guy. Let me say that generally 95% of the people at a pro solo are about like the people at the local level. They know that this is a hobby (even if they occasionally win some money doing it) and do it for the fun. But there are a few that get serious about the competition and when things don't go by the letter of the book, protests fly. There are cheaters and there are people who pride themselves in catching cheaters. It is that simple.

As a first time competitor, even if you get into the trophies you will be given some leaniency. But the basic protest procedure is that protestor has to put up a teardown bond, if it is something that need mechanical work to check. This is usually based on typical shop rates. If say you have to pull a cylinder head, you can do it yourself at the event, and make a few hundred dollars if you are legal. If you are found to be illegal, the protestor gets the bond back. Some people have chosen to not teardown their car, and just accept the DQ. Sometimes this happens because the person knows they are illegal. Sometimes if someone finished 7th out of 11 cars they just say it is not worth it, they know where they finished and had fun at the event. It doesn't happen very often, and in your case I would not worry about it. If you know you are illegal, you might not want to play in the big leagues.

Most protests are not about internal engine mods. Everyone know that the most return comes from handling mods. So where do you think they perform modifications?

I know people who basically do nothing but run Pro Solo's and events of that level. They carry around parts books, factory manuals, factory tech bulletins, etc to prove the legality of their cars. If you get to that level, you will learn what you have to do to keep playing the game.

A thread of me telling you about the items I have seen or heard about being protested would be interesting.