Most late model cars were designed with sway bars and will not operate normally sans one.

The wheel rate always stays the same, meaning (stiff springs or middle rate springs + a sway bar) If you have a stub that has the bar removed, the wheel rate is too soft for decent road sway control.

Measure: 1. distance between the mounts on the frame.
2. The distance between the link holes on the a-arms.
3. distance between the centerline of the frame mounts and
the a-arm link holes.

This should allow you to measure junkyard bars.

Yes, a bar will make worlds of difference. Just dont go too big or you will have to install a rear bar to maintain car balance while cornering. MIZ