I replaced the valve cover gasket, essentric shafts sensor seal and the valvetronic motor seal. All where pretty straight forward to replace once the valve cover was off. Unless the valve cover is damaged not sure it needs to be replaced.

As it relates to the breather hose I really struggled disconnecting it from the valve cover. I probably spent an hour trying to follow the video instructions that didn't work for me. I was able to insert a screw driver between the valve cover and the hose connecter and was able to press the tab release with the screw driver on one side and my fingers on the other and it came right apart. However, in order to push the tabs in to release the hose i needed to push the house as if i were reinstalling it and then it came right off without much effort at all.