1. Note that “sway bar” is kind of a slang term for an anti-roll bar, which is more descriptive of its function. I don’t really know what the term “sway” actually means, so pedantry aside:
2. Front sway bars transfer weight from the inside front tire to the outside front tire. Trying to lift the inside front tire also adds weight to the inside rear tire, this adds traction to a rear drive car that allows you to get on the power earlier when exiting a turn. Especially important when you do not have a limited slip.
3. Rear sway bars transfer weight from the inside rear tire to the outside rear tire. Trying to lift the inside rear tire also adds weight to the inside front tire, this adds traction to a front drive car that allows you to get on the power earlier when exiting a turn. (and reduces accelerative traction on a rear drive) Front drive cars can use huge rear bars that actually lift the inside rear tire off the ground.
4. Recommendations: Hellwig front bar because it is hollow. If cost is important, a solid Addco front bar can be used, but it is heavier. Addco rear bar is the best bang for the buck in the rear, but it does mount to the axle, increasing unsprung weight. If unsprung weight is important, then Firm Feel makes a rear bar that mounts to the chassis (double the $ though). It is best to have a limited slip in the rear before adding a rear bar to a Duster, but not strictly necessary.