Akrapovic Titanium dB Reducer for 911 GT3/RS (991)OP Optional partDesigned and constructed exclusively for the Porsche 911 GT3 (991) and GT3 RS (991), the Akrapovi dB reducer (Titanium) is aimed at driving enthusiasts who need to keep the noise of the exhaust within approved levels during track day use. Made from high grade lightweight titanium, the dB reducer works like an additional muffler to allow extra expansion of the exhaust gases. It is easily fitted by simply removing the Akrapovi tailpipe