Swaybars compensate for cars that have a buggered up "roll centre".

Most cars when you lower them, actually increase the body roll as the roll centre moves further away from the centre of gravity. If you move the centre of gravity down, then the sway bars aren't so important. It's complex science! And for most people, it's so confusing they just don't think about it.

Lowering a car lowers the centre of gravity, but without other changes, the roll centre exponentially moves away from the centre of gravity. Which means lowering most cars (without stiffening sway bars) actually increases body roll.

So if you want to lower a car, you also need to stiffen the sway bars, and change the spring rates. Otherwise adding strut spacers on the bottom of the struts, is mostly to help "roll centre" issues. It's not for many of the reasons that people sell them.

Chris

Shocks and springs are for pothole recovery..good suspension geometry and (including swaybars, panhard rods, watts linkages) are for handling.

Why do offroad cars have high springs?
1. for suspension travel, but the other good reason is that:
2. it keeps the centre of gravity below the roll centre, meaning that when you go hard around a corner, the shocks/sway bars don't have to work hard to keep the car flat through a corner..