There are some really crazy stories around bending the rules. Or pushing human technologies to the limit to achieve the smallest advantages.

Here is one of my favorites:

I read a really interesting print article a few years ago about one of the big F-1 teams (McLaren?) creating the first carbon fiber transmission housing. This was a HUGE deal at the time because in F-1, the transmissions are structural component of the cars. They bear huge stresses for extended periods of time.

The team spent a couple years and tens of millions of dollars reinventing the way carbon fiber is manufactured. It was all very hush, hush. In the article itself, the picture of the transmission was taken from about 20 feet away, because that's as close as the team would let anyone from the magazine get to it. It looked like the made the camera man stand across the shop from the thing and take his pic with a portrait lens.

The big take away at the end of the article was that they saved 50 lbs or so off the weight of the transmission... but the car was already under weight regulations. So they were adding 50lbs to the lead plate that was already on the bottom of the car so it makes weight. The net benefit of all the money and time spent on the CF transmission was to lower the center of gravity of the car 3/4 of an inch and that was considered a huge advantage until the other teams do likewise.

A big reason things like side skirts and vacuum cars were banned was that those technologies were very good at making downforce, until you hit a bump or curb big enough to break the "seal" between the car and ground. Then most of your downforce went away in an instant. Not a very safe thing.

Yes most of the regulation changes in the last 20 years have been focused on taking away downforce b/c without constraints the engineers could design cars that would corner with such force the drivers would be on the verge of blacking out.

The other focus is to try and make passing easier. When you depend on downforce for grip and you get right behind another car, in their air wake, your downforce goes down b/c not as much air is going over the wings. Your grip goes down and you can't pass that car.

A brief aside into the history of aerodynamic advances in auto racing....Chaparral Cars were some of the first race cars to be designed with a focus on the aerodynamic forces at play. While primarily competing in Can-Am instead of F1, they introduced cars with movable aerodynamic surfaces (Chaparrel 2E) and even a partial vacuum (Chaparrel 2J) to increase downforce.