I'm considering getting the helwig sway bars but am worried as the roads where I live (Northern Canada) are fairly rough with quite a few frost-heaves in the roads and I'm wondering if sway bars would make the car want to "hop" more over bumps and especially make the back end want to swing out in turns (on bumpy roads)?

 

As a general rule, when a rear-wheel-drive car is equipped with both front and rear sway bars, the rear bar should have less stiffness/diameter than the front sway bar. Installing too large a rear sway bar can make the rear suspension so stiff that it will cause the inside tire to lift on turns, limiting rear traction. In a high speed corner, it will also increase the likelyhood of "snap" oversteer occuring if the upper control arms bind and cause a sudden increase in the car's wheel rate. You are purchasing a matched set (front/rear) of a well made piece of equipment. I think the Helwig front sway bar is adjustable so during winter months increase the front stiffness to reduce any oversteer tendancy; the car will be less squirrely and want to "plow" into turns rather than the rear end "want to swing out".

John