All 240's had the same mounts. If they haven't been replaced yet I can pretty much bet you that at least one is bad. You can pick up a good set of used ones or just get the Nismo set. The Nismo set is only slightly more than one new one and has both engine mounts and a tranny mount. Most S13's I work on have at least one bad/going bad mount. If the motor runs smooth but moves around then at least one of the mounts is bad.