RSR has me at a 1:24.012; lots of lag spikes at my new place and one out of every three laptimes gets uploaded to the RSR database.
This setup will not magically fix the car if you are struggling just to get around the track. The 98T in AC splits the userbase into two very tangible groups:
1. Should probably be in a real race car / are already in a real race car
2. Everybody else
If you're part of the minority that can drive the 98T, this setup works pretty much anywhere and can rattle off consistent low 1:24's in Leaderboard/Qualifying trim. You can drop into the 1:23's if you feel like playing russian roulette with the turbo lag.
There is no "stable" setup for the 98T; it will try to kill you, on average, 3.74 times per lap. Don't be like some guys on the official AC forums who whine that they can't drift like Chris Harris after five laps in a car. This is exactly where we find out who can drive, and who can't.