I do love all forms of racing. I have been to F1 races, NASCAR, Sprints, 24 hours of Daytona, and Indy probably 20-25 times. NASCAR fans are the most knowledgeable. F1 fans the most team loyal. Sprint fans have the most fun.
I managed a race shop for many years and yes. EVERYONE DOES CHEAT. In the 1980's thay had what was called The Playboy Cup. It was a series of 'identically' prepared Porsches. We had a guy come in and said "I want to go a little faster than the rest, but I don't want to get caught." We milled his cylinder head ( this increases the compression, hence more speed.) The next week another guy came in and said " I want to go fast enough to beat the first guy." We milled both head, and block. We ended up making stroker kits, for the crank, fly cutting pistons, and going with larger valves. By the time the series was over we had modified ALL the cars.
You may have heard the story about A.J. Foyt who won a race and was called in to tech to check for violations. Now tech KNOWS everyone cheats but not how you are doing it. They thought Foyt was running a larger tank. They removed his tank and measured it. They didn't find a problem so they told him he was free to go. Without thinking he got in the car with NO GAS TANK, started it up and drove it away. He had the roll bars modified to hold fuel.

__________________
Gun control WORKS! That's why it is so safe to walk the streets of L.A., Chicago, and D.C. at night.