Your uppipe riser bellow most likely blew from vibration. If the cap isn't supported they will crack eventually... Also I'm not much on uppipes and manifolds either. In a supercharged or N/A motor its nice to allow the exhaust to escape as fast and smoothly as possible. But since we have turbos our engines make power from exhaust pressure. Smoothing out the bends and and gasket matching doesn't change the pressure. It does however help exhaust exit faster, but again our trucks are driven off exhaust pressure. Just my take on it, not trying to step on anyones toes though just giving my honest 2 cents. If I had the spare money, sure I'd buy a set, but you won't see me saving pennys for them.
But please prove me wrong if I am missing something, I'm here to learn also.