How do you drive RR Rufs? Very carefully. Serious. Grab hold of the wheel, grit your teeth, clench your cheeks, and mash the throttle.
If you want to drift them, just drive them like you would any other car. They will drift whether you want them to or not. Lift-off, on-throttle, braking, etc.
If you want to focus more on grip driving, you may have to add some ballast to the front, as well as tame any more oversteer with suspension settings (softer rear, harder front, add a GT Auto wing to the BTR, blahblahblah). Slow in, fast out. Brake and accelerate going as straight as possible. Prepare for some counter-steer in fast esses. Left-foot braking with some simultaneous partial throttle if you're entering a tight corner after a medium-to-long sweeper.
Good luck!
👍