I use MDM first few laps out to feel where the car likes to step out. Once I feel comfortable with the track I drop the MDM
I lose a lot of time with it on and I can't 4 wheel slide to get on the power out of the corners accelerating quickly.
Also if you clip an apex to straighten out and launch the car through a corner it drops all the power thinking your car is getting air
But it's a useful learning tool before you throw in the car control
At the time attack practice day I shed 5 seconds once the controls were off and more time once I started getting on it