Just wanted to know if the 12MM MANIFOLD INSULATOR TO SUIT VE COMMODORE LFX/LF1/LFW SIDI V6 Factory gasket will replace the factory gasket or if you need to install the factory gasket as well as the insulator?

While this manifold insulator kit could replace the factory O-ringed gaskets between the plastic manifold and aluminium cast adaptor, it's good practice to simply retain the factory O-ringed gaskets when installing the manifold insulator kit.