How to beat Finn’s challenge with 250 gto

Locked in the 250 GTO for Finn’s challenge as it breezed through the last tempest tier 2 and I checked my dyno and seen I’m running 9.4 and only need 10.1 to win the car but as soon as I started the race it says max PP is 399???? How the hell am I supposed to beat it with such restrictions 🤣 anyone have a tune for the 250 gto that will get me the times I need? Does the max pp increase as the races go on? At a loss here can’t find a tune that works