[RevNev]

The base model M4 isn't performance optimised to reach it's lap time potential on a race track. However, BMW produce faster variants with the Competition Pack, CS, GTS, and GT4 which is dedicated race car.

We don't need to reinvent the wheel or try to adopt GT3RS Porsche engineering onto an M4 when the factory has already optimised it's performance potential.

BMW didn't fit 19" front wheels to the CS and GTS and 18" wheels to GT4 because 20's are better. They took 20's off the front to reduce understeer without excessive camber and consequently, the car is faster with 19" front wheels.

It's unlikely that anyone driving their road cars on race tracks are close to the car's potential to determine short falls in the base model and yes, I have an M4 Competition and have driven it on race tracks and for stock car, they're excellent.

The point I'm making if you want to make it potentially faster, you can simply follow the factory performance optimisation process.

Here's an "all about go" example.