9th Mod, Rear Sway-Bar Upgrade

WOW, I have to say, by far the best mod yet. You can see in the picture the difference in size. The stock one is 17 mm in dia. and the new one is 22mm. Also the new one has 3 mounting holes, the further out ones being softer than the further in ones. I mounted mine through the stiffest hole so I could really really feel the difference.

The ride difference was noticed immediately. The ride is stiffer in the rear, and the body lean as little as it was has been cut to almost zero.

There is almost no sensation of speed in the corners. Autocross this weekend is going to be a total new experience.

The sway bar was $144 from a online store from Boulder, CO and I would HIGHLY recommend a 22 mm sway bar for the rear of your WRX, or upgrading your sway bars.


I did a quick study to see what difference the bar made analytically. I jacked up the passenger rear tire until it was Approx 1/8" off of the ground. Then I measured the space between the top of the tire and the wheel well.


Then I calculated the difference between the space from the jacked up, and ground side. Then I compared the difference after the sway bar. Before the bar there was a 2 1/2" difference in wheel clearance. Afterwords there was a 1 1/8" difference. This is a 55% reduction in the deflection of the rear "axle". I don't have the tools to calculate how much stiffer the bar is, but it seems it will take 55% of the rear end roll out.

I found a chart online, and switching from a 17mm to a 22mm adds 180% stiffness. With the stiffest seting being further in than stock, there is a chance this sway bar has 300% the stiffness of the original bar.