2006 Chevy Malibu one piece exhaust manifold and catalytic

First of all thank you so much for your donation. You would need to replace it with the set up it came with from the factory to make it legal. If the exhaust manifold and cat are together they must stay together. So you need to replace the exhaust manifold cat?Also what price's are you getting quoted?Are they from the dealer?What state do you live in?That matter's when looking for replacement cat's.