Here's an alternative that has worked for some of us, even in drag racing.
A front-motor, rear-drive car twists the frame diagonally on acceleration. The left front and right rear get light, while the right front and left rear get heavy. That's why you always wear out the RR tire first.
If you have large coil springs in the rear, install an air bag on the RR only.
If you have coilovers or leafs, install an air shock on the RR only. Move the battery to the EXTREME right rear of the car.
Air up the unit, increasing pressure a little at a time until you get two black stripes. An open diff drives easier than a locker.