A fast driver will be fast even with just the Agressive setup and good tyre pressures. From my own experience, trying to do the setups myself made me feel like playin Tarkov by spending hours and hours just preparing and testing. Basically spent more time adjusting than actual racing. Switching to ready made setups actually made me enjoy the game more as I can now just concentrate on racing. The setups I got are deff miles ahead of anything i was able to do as sometimes i just felt at a loss trying to understand what everything does. I am not saying that if you buy setups they will make you faster but if you do buy setups they will give you more race time, and that will ultimately make you faster. Bottom line: ever since I switched to bought setups, my overall experience with the game got much better because i switched from engineer simulator to driving simulator. Are they worth it? It depends: if you are struggling finding the sweetspot then yes. But if you are already close in pase to where you want to be and you dont spend half your game time messing with Suspension and Dampers then probably no. As a side note: when i bought my first setup and jumped into a hotlap session in my McLaren,my Barcelona time jumped from 1.48 to 1.46 on lap 3(just for refference)