KYB is one of Japan's premier shock builders. Their AGX product provides adjustable dampening without having to move to a coil-over suspension. The AGX struts are generally a little more firmly-damped than stock struts, so they work great with moderate lowering springs.
Adjustment is with a knob on the top of the shock, both front and rear. Adjusting the rears will require removing the rear seats to access the adjustment knob.
Adjustment is four-way front and rear, and adjusts both rebound and compression simultaneously. Softest setting is slightly firmer than stock; hardest is very stiff.
Fits all 1993-2001 Impreza. Set of four struts. Note: Older AGX rear shocks had an adjuster knob on the lower side. Newer ones have a top adjustment, like the front. It's still the same internals. Photos are representative; actual product appearance may vary slightly.