I just received a call from the second customer to have this issue in a week. ZZP apparently has made changes to their cat-back system. It now includes the secondary catalyst pipe or "test" pipe that bolts up to the flange just over the axle. Where the system used to bolt up to the Anaconda, there now resides a slip-fit joint instead of a 2 bolt flange. This will require a muffler shop to either cut the flange of the cat/test pipe and weld it on to the cat-back, or make a flanged pipe to bolt to the Anaconda, and then slip into the ZZP cat-back. Either way, this will add expense and down time to combining these two parts which is a shame. I have lots of customers utilizing this set up and they are all very happy with the results. Even with the added hassle, I still think it's a great combo. I just wanted to post this so you guys won't be taken by surprise.