When I first got my wagon, I couldn’t believe it never came with a rear sway bar. After just a couple corners, it is very evident it’s missing one. Subaru decided that from 92-94, the L-trim Legacy’s didn’t get a rear sway bar. The frame still has tapped holes meant for the brackets, but they just never added it to those years and trims.
So there was a very simple fix for this; I went to the local pick&pull yard and yanked a 95-99 Legacy’s rear sway bar, C style end links, mounting brackets with bushings, and lateral links with the end link brackets.
Then at that point I just cleaned up the mounting spots for the brackets, I ran a tap through all the holes just to clean them up. On the passenger side, there is going to be some trouble with the hole that is almost completely under the filler neck for your gas tank, but with a pry bar, some gentle careful force, and removed bolts you can move it to the right spot where you can access the hole. Bolting everything on is very easy to do, refer to pictures to see how it is supposed to look. It made a HUGE difference in handling, even though the bushings on the C links are shot. I’m planning getting some Whiteline replacements and a 22 mm sway bar and then things should be perfect.