Can I suggest you drift the car first... then lock the diff if you are having difficulties with drifting..

Its easier to learn how to slide with a Stock car then it is with a car that you mod before you drive..

You need to get a feel for the car stock,before diving into doing drivetrain mods.. Some cars don't require any diff locking and some do..

Try Stock first... then lock the diff only if YOUR not happy with the way it slides...