So the newest Manufacturers' Cup race, and a lot of the surrounding setups, discussion, etc, is proving that despite some of the improvements in the last patch, there are still issues with the PP system. And there are always going to be issues, as long as the current philosophy of taking the car's entire setup and simulating tests, is in place.
I don't know why PD decided to go with the system they did - maybe they thought that by doing so, they would also be able to "balance" a good setup, versus a bad setup. But this is fatally flawed, because a "good setup" versus a "bad setup" is not just a fixed, linear thing. In reality, any setup will be better in some situations and worse in others. So with the current system, the "meta" will always be to find setups that do very badly in the PP simulations, but not quite as badly on the actual racetrack, which allows you to pile on more power, downforce, whatever. No amount of "fixing" the PP simulations and calculations will ever help that, because the simulations will always be different from the track, and there will always be advantage to be gained by finding those differences.
There is a solution, though, and it's quite simple.
Just make it so setup doesn't affect PP!
The PP calculations should be run on the car with all of the default settings for the parts you have fitted (suspension, gearbox, differential, excluding ballast and power restrictor of course). Thus, there would be no ability to tank your PP with weird suspension, gearing, or the like, as is seen in all of the current "meta" setups. Yes, this would stop the grinding exploits once and for all. But with all of the current ways to gain PP, I would much rather improve the game and the racing overall then worry about getting all of the cars slightly faster. This also means that tuning can, finally, be about only making the best handling, best driving car, just like it is in real life, and not about gaming the system. This will also make it a lot easier to drive cleanly and not having cars trip over each other because of weird suspensions, top speed, power differentials, whatever.
Possible issues?
I don't know why PD decided to go with the system they did - maybe they thought that by doing so, they would also be able to "balance" a good setup, versus a bad setup. But this is fatally flawed, because a "good setup" versus a "bad setup" is not just a fixed, linear thing. In reality, any setup will be better in some situations and worse in others. So with the current system, the "meta" will always be to find setups that do very badly in the PP simulations, but not quite as badly on the actual racetrack, which allows you to pile on more power, downforce, whatever. No amount of "fixing" the PP simulations and calculations will ever help that, because the simulations will always be different from the track, and there will always be advantage to be gained by finding those differences.
There is a solution, though, and it's quite simple.
Just make it so setup doesn't affect PP!
The PP calculations should be run on the car with all of the default settings for the parts you have fitted (suspension, gearbox, differential, excluding ballast and power restrictor of course). Thus, there would be no ability to tank your PP with weird suspension, gearing, or the like, as is seen in all of the current "meta" setups. Yes, this would stop the grinding exploits once and for all. But with all of the current ways to gain PP, I would much rather improve the game and the racing overall then worry about getting all of the cars slightly faster. This also means that tuning can, finally, be about only making the best handling, best driving car, just like it is in real life, and not about gaming the system. This will also make it a lot easier to drive cleanly and not having cars trip over each other because of weird suspensions, top speed, power differentials, whatever.
Possible issues?
- Drivers with better setups will do better - This already happens, it's just about gaming the PP system instead of actually making a good setup. Making a good setup should be part of racing, and it appears as though there will always be non-tuning/BoP races in all modes if you don't want to get into that.
- Certain parts like differentials can still tank the PP - This can be solved by using the higher of the PP values for the fitted part or the stock part.
- Waah waah I need to grind - There are plenty of ways to make over a million credits an hour in the game already. You don't need to have every car in the game right now.
Simple fix 
Polyphony, keep it simple... simple is good!
