I think a lack of flex pipe or flex joints on your exhaust is why the manifold cracked so bad. Remember that's alot of weight and movement, plus you have the manifold bolted to the engine, then couplers to the intercooler, plus the slight movements the engine makes regardless of having stiffer mounts. Hopefully it holds up better now. But I've noticed people with flex pipes on their setups tend to not deal with cracking or stressing out the welds as much.
I think a lack of flex pipe or flex joints on your exhaust is why the manifold cracked so bad. Remember that's alot of weight and movement, plus you have the manifold bolted to the engine, then couplers to the intercooler, plus the slight movements the engine makes regardless of having stiffer mounts. Hopefully it holds up better now. But I've noticed people with flex pipes on their setups tend to not deal with cracking or stressing out the welds as much.