Deleted... New thread posted.

 

not sure what the stock size of the pipe is but if the end of the pipe after the cat is 2.5" then i would say it is that. are you sure that was the stock muffler and pipes after that? could account for the bigger pipe size after the muffler

IMO the bigger the pipe the better the performance, letting the engine exhale if you will as best it can

there are lots of mufflers out there that will give you a great sound that could be better than just an open exhaust for not a whole lot of money, but if thats what you want

dont know what to say about the sound becoming quieter