Had the Ultrex short shifter in my old MY08 wrx, had no issues with installation or the unit itself.

Do you need/want the short shifter or are you trying to firm everything up a bit?
I would also look at the shifting bushings at the same time, makes a world of difference over stock.

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2015 Forester XT Premium
2020 VW Tiguan Allspace
teejay: If I wanted a comeback Id wank in front of a fan