You could, but there is not (that I'm aware of) an aftermarket OEM style bushing for the car. Ford and the 3rd party suppliers only sell arms. Maybe I'm wrong here?
There are aftermarket performance bushings available. I think it would be easiest to remove the arm from the car to install. Also, I cannot advocate doing just one side of the car, it would make the handling pretty wonky, maybe unsafe. Both are my opinions, YMMV.
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2008 WRX daily driver
2003 ZX3 23D Autox Car 42 FSP
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