The more research I did about the o-ring the more surprised I got of how unaware I was about this issue. Thanks guys this saved me a lot of time and headaches down the road.
Oh and I looked more into how to clean the headers... My coworker recommend I port the headers, recommended a good place but seems a bit excessive don't you think?
My other option is to get a couple flex-hone's, do it myself and pocket the money for a tune afterwards?
And last question, I promise, will the sensors reach the secondary cats if I were to relocate them?