Don't go too stiff on the rear bar without a limited slip diff, you will be lifting the inside rear wheel allowing it to lift off the pavement. ( Remember, anti roll / sway bars just transfer weight from the outside to inside wheel.

With your front suspension, clamping a 2nd bar the original might be a better option. ( or adding a bar in a more facing forward conventional location. )

You can get straight bars with splines on each end and clamp on arms.

Speedway Engineering's Sway Bars

Sway Bars