exhaust leak pace setter headers and zzp 3 inch cat back

[2000supercharged]

i have been fighting exhaust leaks for ever and finally fixed 95% of them but I think I still have one left but I cant hear it unless im driving next to a wall or a car but its not a huge leak I have already smoked it with sea foam and don't see any real leaks and im wondering if the flex pipe that came in the pace setter kit leak very commonly because I don't see any leaks but I can also hear it at cold start so any suggestions? could it be the flex pipe?

 

[JDrach]

My SD's sound to have a leaking area at the front manifolds. Does it make like a rattling air like noise? Rev it up and see. Try to pin point the section of exhaust where you can hear it. Single walled flexes do tend to leak, but mine and some others who have a single walled flex have not yet.