The infamous Exhaust Seal gasket which connects from the Catalytic Converter to the exhaust pipe. There is a seal gasket and it wears out fairly quickly and the hardware isn't appropriate to eliminate the problem. Its a loud squealing chirping noise coming from under the car usually heard at idle or in drive at a stoplight or drive thru. It is a design flaw and as far as March 25th 2015 Mazda has no fixable solution.

I've contacted Mazda customer service and they have updated hardware but it only temporary for a few months eliminates the noise, there is no solution and once the warranty runs out well...you're out of luck. The terrible thing is it can damage your catalytic converter. They told me if it's not fixed with that annoying exhaust seal noise. So more damage can occur without any solution to fix it, great...frustrating yes and still no fix. Everything else is great on the vehicle. Mine is a 4cyl.