(VW67a / YTP18). Polo Gti 1.8 TSi (6C) 2015 on Exhaust System Resonated Inc Sports Cat Downpipe. Resonated - Quieter. What is the difference between resonated and non-resonated systems?. Resonators are box chambers incorporated into the exhaust system, which are used to make the exhaust quieter, by cancelling certain sound frequencies.
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