I feel your pain. during the summer of 2014 I replaced my gaskets with part number
F31731 from Car Quest. That fall we developed an exhaust manifold leak, and when that was fixed, the mechanic said we needed new exhaust gaskets as well, so he installed the genuine GM ones. Not sure which part number he used
15150413 donut OEM
15170285 donut GM
By time we got back to Iowa in the spring, they were leaking, so once again I purchased two of these Robot Check
but this time I replaced the bolts and nuts as well which I purchased from GM. Havent had a problem since...Knock on wood.
I have read that part of the problem is the distance from the manifold back to the support, and someone has suggested that a support be added for better stability of the exhaust pipe.