Way too extreme for me and I'm sure my neighbors would crucify me if my car was that loud. That's like wake up the dead loud or let every cop in a 10 mile radius know you're getting on it loud.
I'm at work so wasn't able to watch the entire vid .. but I jumped around and the bits I did see sound phenomenal.
Is the car tuned? I want to go the high-flow cat route as well and I am trying to budget everything out. Not sure if I can get by without a tune for a bit or if it's better to do headers+tune at the same time. As far as I have researched, even the high-flow cat solutions tend to throw a CEL without a tune.