Not very constructive, but I need to share this: I’m about to give up… after having had gold on every single other license, mission and race on GT7.
I play with controller and automatic gear with « hard » difficulty (whatever that means for those endurance races).
Tried corvette, amg, Mazda, Subaru BRZ, Supra, Alfa, RCZ… 1 or 2 stops, RM or RH, saving fuel or not, … the best I get is 28 seconds behind the winner!
I can achieve the 57s or 58s several times, but not on RH or on worn RM, and I suspect that this is what is killing me. On RH Im too often on the 59s and when worn, I sometimes fall to 2+ mins.
Last attempts were with the Mazda that seems to have great fuel economy, but without luck.
Any other recommendation is welcome, I’d like to continue but I’m spending my life lapping Maggiore, and it’s too much ;-)