Not on the V6. There's a weak point on the gasket which vents to atmosphere. There will be no water, or oil loss, and a barely perceptible loss of power. It will cause a very similar sound to the exhaust manifold blowing, but can go on for miles without getting worse, or causing an issue.

Hence why I said be very sure it's the exhaust manifold before attempting a replacement. I'd want to be feeling the gas actually coming out of it before I considered pulling the engine apart.