Complex sentence: Meanwhile, in 1963 Jaguar had introduced the Jaguar S-Type as a development of the Mark 2, in which a mid-scale version of the Mark X independent rear suspension replaced the Mark 2's live rear axle.
Split into simpler sentences: Meanwhile, in 1963 Jaguar had introduced the Jaguar S-Type as a development of the Mark 2. It utilised a mid-scale version of the Mark X independent rear suspension in place of the Mark 2's live rear axle.