For balanced power gains and optimal sound-deadening, a sport muffler gets the best results. This can be bought aftermarket.
https://www.availableonline.co....m.au/mufflers-101-re

Mufflers 101: Reducing Noise, Increasing Efficiency | Available Online
www.availableonline.com.au

Mufflers 101: Reducing Noise, Increasing Efficiency | Available Online

Experience improved sound and performance with our range of car mufflers. Shop aftermarket mufflers from trusted names in the industry.