Complex sentence: The S-Type was a major redevelopment of the Mark 2, using a mid-scale version of the Mark X independent rear suspension to replace the Mark 2's live rear axle and featuring longer rear bodywork and other body styling and interior changes.
Split into simpler sentences: The S-Type was a major redevelopment of the Mark 2. It used a mid-scale version of the Mark X independent rear suspension to replace the Mark 2's live rear axle and featured longer rear bodywork, among other styling and interior changes.