@Wireworm5 A lot of cars have stable power slides at high speed using drift tires whilst using race/track performance suspension and differential.
The key would be hitting the turns high in the corner going towards the lower end of the turn while maintaining 205~210 MPH power sliding half way through the turn, then around the 5/8 mark of the turn at the right moment use nitrous on your way back UP towards the wall making you exit the turn at 215~220 MPH.
For your fastest runs you'd want NOS reset + NOS Draft, 5+3 tank to help maintain your NOS replenishes when you're up against people hitting 1:26/1:27 mark, the drafting will help due to NOS reset CD when you're trying to maximize your speed after each turn.
My best time is clocked at 1:30:88 on my FD3S, TCS turned off WITHOUT using nos, I am using race ( Blue ) suspension on Drift Tires and Track Differential, engine swapped for the 3.8L V8.
Using nos on that car is nil at around 195 MPH, the acceleration of the car itself is the same amount of speed as using a nos so I never nos'd on the resort using that car.
You'll need to practice more again using your same vehicles on different setups on your sus/diff/tires for sliding on that turn properly and perfectly.
I'm not one to use the RSR or the beetle for the OP NOS acceleration on that track, I could care less about the other drivers using those cars, I stick with my tuners and repeatedly go through every track I time attack on different setups and feel how the car responds on entering and exiting corners.
