Kartboy's solution for the new rear subframe and rear differential lock down system. Machined aluminum insert to lock in the rear diff bushing inserts. Four Carrier inserts to keep everyone happy. Stealth black so the AutoX protesters will never know. Install with hand tools in under an hour.
This Part Fits
- 2015-2020 STI Kartboy Rear Diff / Carrier Wedge Lock System
- 2015-2020 WRX Kartboy Rear Diff / Carrier Wedge Lock System
|Additional Warranty Information||No|
1 customer reviews
This should be the first upgrade on any WRX/STi
The Kartboy rear diff wedge/subframe bushing insert kit on my 2019 STi has changed my life. Long review warning; I'm verbose. Sorry, not sorry.
I had previously installed the Perrin aluminum diff inserts and poly subframe inserts on my old '08 WRX. They were a bitch and 3/4 to install, so I had been procrastinating, expecting this to be similar. I had picked up the kit a while ago, but it has just been sitting on my desk waiting for me to be inspired enough to install it.
I finally got off my ass today, and it was one of the easiest installs I've ever done. Everything fit perfectly, without any drama getting the bushings to align. I think total install time was maybe 30 mins, garage door open to closed.
I knew upgrading these bushings had made a massive difference in my old WRX, but I assumed the STi would have had stiffer bushings from the factory, thus I should perceive less improvement. As Social Distortion once sang, I was wrong.
I love my Nameless Performance exhaust, but this was probably the most beneficial upgrade I've done to the car to date. I've noticed zero increase in NVH, but so much on/off throttle slop is gone. The drivetrain is almost as responsive now as when I had Cusco motor and trans mounts, and aluminum diff mounts on my old car, without all the effort that setup entailed.
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