Why You Need So Much Loud?????
Want To Scare Dogs Or What 
It Also Depends On Engine Back Pressure...Resonator....Downpiping Size....Headers And So On..........!!!
Not Just Muffler Is Held Responsible For That
And Installing Too Much Open Piping Results In Almost Zero Low End Torque...
My 500$ Advice...(no Way I am gonna say it 2 cent advice
)