Yes if you want oil vapors back into your motor to lower your octane. If you want max performance then no. All the port on the valve cover is to vent the pressure back into your motor due to emissions that’s why they route it back to the intake side so it burns off in the motor. Now take your intake off and look at the pools of oil in your intake manifold and tell me if you want all that back inside your motor. I pulled mine off and cleaned it all out so my TB and IM are spotless.

 

Thanks. I just installed a catch can and wondered why those were left in the system. I’ll make sure to remove them.

 

No plastics except for the front, have to check my thread but about 7.5 lbs lost from removing them.