Project Gen3 STi – Wheels, Bars, and Bits


Subaru Impreza WRX STi GR rear sway bar OEM versus Progress 22mm end link heim jointThe OEM rear bar and end link compared to the new Progress replacement. The fixed position end link on the OEM rear bar creates a potential problem area for lowered cars in that it can increase sway bar bind. Notice also that the OEM rear bar uses a press fit collar for bushing retention whereas the Progress bar has a welded collar to keep the bushing in place. The grey powdercoating is also a nice touch.
Subaru Impreza WRX STi OEM rear sway bar GR
The Progress rear bar is over 4mm larger than the OEM! We feel that a big rear bar is essential on the heavy AWD STi, we also feel it is necessary to have adjustability and you can see the 3 position holes to soften or stiffen the rear bar. This is a different approach than say the Autocross BRZ where we worked to maintain the balance of the OEM sway bar size stagger. 

The install of the Progress bar is very straight forward as well with the only extra step being the end link adjustment and installation. For this we used the same floor jack method of loading the rear suspension and adjusting the end links to the proper height. This is slightly more challenging on the rear of the car as the end links lower mounting point is within the channel of the lower control arm. We found it helpful to apply grease to the end link spacers to hold them in place and also allow them to move freely within the lower control arm. We torqued everything to spec and re-installed the muffler but not before we took some pictures.


Progress STi WRX Impreza rear sway end link installedHere you can see how the end links sit within the channel of the lower control arm. Our grease trick worked extremely well to position the end links in place! We found it easiest to bolt the end link to the bar and just pivot it into place without the lower spacers to adjust height. Once we had the correct height so that the bolts slipped in place with the suspension loaded we greased up the spacers and slid the end links into the lower control arm. Also notice the bushing retainer bracket which uses a solid backing plate. This helps to strengthen the entire assembly and that is necessary as the bracket mounting point is a stamped piece that hangs down from the chassis. We will likely add bracing to this location in a future installment. 

Here's the only bummer, as of right now we can only offer a small seat of the pants assessment for the sway bars given the weather conditions here in WI. Surely -11 degrees is not the proper weather to assess improvement in lateral grip due to a decrease in body roll however we will provide updated feedback as we enter the track day and autocross season within the coming months.


Progress rear bar installed WRX STi GRNow that's making Progress… OK OK I have no future in marketing tag lines. Did we mention how well everything fit and how nice it was to work with the muffler off the car? 

With the car still up in the air this was the perfect time to improve some other areas as well and that is where the “Bits” portion of this installment comes in. Specifically our friends at Go Fast Bits and Kartboy had some parts to improve the driver interface in the form of stiffening the shifter and engine and also reducing shifter throw. The EJ is known for moving a lot within the engine bay and the OEM pitch stop is very sloppy. Our first order of business was to drop kick that floppycock plastic crap to the shitcan.


Kartboy pitch stopWe really like Kartboy products, sure the quality is great but the candy in the box just makes everything that much better. Oh and if you read any of my previous stuff I am a sucker for packaging. Kartboy has their own tape for boxes with their logo on it… Bangin' 

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