I can tell you now TRR mufflers are extremely good..if u buy one of theyre top end mufflers especialy.
I have a 10' by 7' inch stainless oval muffler with a 5 inch outlet tip on it.
They are stainless packed..not shitty fibreglass that burns and blows though after 3 months..and they are completely straight thru true 3 inch with a proper perforated baffle that continues throught the tip..its super quiet,on and off boost...I took it off one day to see if it was a restriction..absolutely no better performance wise,and the cars sounded attrocious,it really is a muffler that works....as in it doesnt hinder performance but will slash the noise heaps.
It was a little on the expensive side though...get what u pay for though.
Ask 87Vr4..his Stainless Magnaflow Barks like a pitbull beat with a stick,cool but if u drive it daily,it may get too you.
And then youve got people with no muffler,thats fine if its only small pipe,But u go three inch,it will cause a fukin lot off noise.