Yeah I know that, Im just asking what would you use to replicate the tyres that are used in real life...
That could be almost anything.
Instead of matching tires to PP, try to match tires to the type of racing that you envision.
Comfort tires are generally thought of as regular road tires. Comfort Hard for cars like the Prius, CM for older sports cars and inexpensive modern sports cars like the 90's Corvette ZR1, Civic Type R, etc. Comfort Soft for mid to high end sports cars and super cars like the F430, Viper SRT-10, 2009 ZR1, GT-R.
Sports tires can be considered as a group containing street legal R compound tires and full on race slicks. SH is a good match for cars like the 430 Scuderia and Viper ACR. Sports Medium would be the absolute best street legal tires or the lowest grip racing tires. Sports Soft would be low end racing tires, I like to use them with the ~300 hp touring cars like the Altezza and 330i.
Racing tires are for high end race cars like FIA GT, LMP, and F1. Thankfully in this performance, difference in downforce modeled in GT5 create plausible performance gaps between these cars even when they run the same tires.
Now what you would do when trying to pick a tire for a race is try to determine what the cars that you will be entering are supposed to represent. If they're nearly stock road cars, then comfort tires are probably best, though occasionally you could go for Sports Hard. If the cars are are road cars modified for racing, then sports tires are probably a good match, especially Sports Hard to Medium.
Heavily modified road cars and road cars fit with racing tires would probably be able to achieve performance seen with Sports Medium and/or Sports Soft. In reality road cars probably wouldn't be able to take full advantage of race slicks, so the upper end of the sports tires are probably a better match for simulating full racing tires.
Road cars modified to the point of being purpose built race cars and cars that are purpose built race cars get Racing tires.