[Back in Black]

The front sway bar is always larger than the rear sway bar, for a front engined car. I don't know what actual dimensions you would need, but your front/rear weight bias, based mostly on your motor weight, is the deciding factor. Also, the heavier the sway bars, the softer the springs needed for a good tight race car like ride. That gives a softer more comfortable ride, but great handling, all other factors equal.
You definitely need front/rear sway bars !! Install with the new poly bushings if at all possible !!