According to the HZ parts books all models had the silencer listed as a part, it doesn't show it as an option. section 8.009 part 2812211 and clip 3934260 x 16 qty (which is now the Rare Spares part H1294 as a complete kit) The newer material offers better sound absorption, reduced weight and no itchy glass fibres. They use thermoplastic heat resistant fibre technology as required on the cars being built today. Unfortunately some materials and processes used in the past cannot be replicated due to OH&S factors in place now.