My Flo-Pro fit great. I imagine that all 4 companies make a good product but you will probably still find some people who have had bad luck with any one of them. What exactly do you mean by "finish"?
Of the four, MBRP is the only one that I know makes a 304 SS exhaust. Unlike 409 SS, 304 will polish and will not corrode the same are 409. 409 will last a long time but will look just like your stock exhaust after while.
Of the four, MBRP is the only one that I know makes a 304 SS exhaust. Unlike 409 SS, 304 will polish and will not corrode the same are 409. 409 will last a long time but will look just like your stock exhaust after while.