Sloooooo down! Use that search feature. all your questions have been asked before. Some are asked monthly.
Get to a VCA event, Viper Days event, or a gathering of Vipers at *******, and listen for yourself. Exhaust sound is sooooooo subjective. What I may think is awsome, you may thing sounds awful. There are many systems out there and all kinds of combibations of hi-flow cats, Snake Oyl sub, with or without cats, Corsa, B&B, Borla, Belanger,etc.
Most of the systems that start with "B" boom or drone. Corsa does not. Gains are all similar so bang for the buck on a cat-back is not to real. About 1k or more for 20 or less hp.
Good luck!