I just changed the diffuser. I bought the part from thatgmpartsguy and used the dyi on this site to figured it out. It did take a few hours only because I was being cautious. My exhaust is only an axle back, but I will soon add a resonated x pipe probably magnaflow as Borlas is crazy expensive.
I have more exhaust videos on my phone if you'd like me to text them to you just send my your number. I have a cold start and also some from the interior.