Milltek Sport | RACE Cat-Back MK6 RMilltek Sport RACE Cat Back (Non Valved, Non Resonated) Volkswagen Golf R MK6 Milltek Sport's range of Cat Back systems are perfectly suited to cater for anyone looking to improve their sound and aesthetics, designed as a direct replacement for the original system, available in multiple configurations enabling the owner to choose the increase in volume of their exhaust and or add a more suitably aggressive tone. All our products are made from 304L