I don't think any connections are leaking, as I don't hear any ticking or see anything funky. I just had the dealer I work for install it yesterday...its just loud as hell and makes your ears tingle.
I still have my stock resonator because a tech swiped it before they threw the catback out. Its 2.5", just like the rest of the exhaust. Should I swap the ZZP res with the OEM res? Is it worth the effort? Some people are telling me to put a long Magnaflow muffler in place of the res, but I'm afraid that won't cancel out the frequencies causing the issue...