I have a 99 Subaru Legacy wagon with a pretty common problem. The rear-view mirror in these cars likes to droop, it adjusts itself downward whenever you go over bumps. It’s a problem that seems to effect all of 2nd generation legacys (1995-1999 aka the BD or BG chassis). It’s mostly due to the design of the mirror, the ball joint is on the back of the mirror rather than the top, which means in order for it to hold it’s position there needs to be a lot of tension in the joint in order to resist the force generated by the weight of the mirror whenever the car hits a bump.
Having owned several 240SXs I noticed that the S14 chassis (1995-1998) uses a very similar size and shape mirror as the 2nd gen Legacy:
As you can see they both use a similar length arm with a similar shaped mirror and a similar 3-bolt mounting flange. The Legacy mirror is black but the gray color of the 240SX mirror doesn’t matter because it actually matches the gray headliner in the legacy.
What’s not the same about the mirrors the adjustment join:
As you can see the 240SX mirror has the adjustment joint on the top of the mirror which means that any bumps or vibrations will have little effect on the adjustment. Having owned 3 separate S14s I never had any problems with the mirror falling out of adjustment, nor have I ever heard of it being a problem with other owners.
AMAZINGLY the bolt holes on the mounting flange line up perfectly in the Subaru for a 100% bolt on replacement. I used the plastic cover from the S14 mirror since the mounting flanges are shaped slightly different but it looks right at home in the Subaru, and no more droopy mirror.