I talked with a few mechanics and they just will leak. Even if the exhaust seals... it will leak water when cold. I wouldn't worry too much about it. Better than it staying in the exhaust. If you have a leak, try and get the car in the air, and start it... listen to the pipes and try and find the leak. My brother works at a dealership, so I just went in while he was there on a Sat and put my Z on a lift to find mine... ^_^