gentle gto

Hey Gents. I have this fume issue with the Goat since Oct of last year. Smells like an exhaust leak. No leaks detected both my tuner and an exhaust shop. There was a oil leak in the valley and it seem to be leaking on to the headers,so I had that fixed. Smell is still there. Then I was told that the mid pipe gaskets were bad.Had that swapped with new ones.Smell still there. Then I was told it was the cats.You guessed it, had them swapped out with new Kooks. Smell is still there. The smell is sort of pungent. It lingers in my garage. No signs of fluid leak anywhere. It can be smelled while idling. What gives ?.Thanks for any helpful suggestions