According to Eibach they don't work on SHOs because it puts the ride height sensors out of range. The sensors detect suspension position, and with the lowering springs the sensors always think the suspension is compressed, which makes the SARC controller put the struts in hard mode. I have heard that flipping the sensors upside down will correct this problem, but I don't see how that would work. Eibachs will work fine on 99 non-SARC cars.
Kirk recommends that for any car you should cut down the strut shaft to adjust for the lowered height. This will keep the piston in the center of the strut body and prevent the piston bottoming-out.