crash95

i need help??? on the drivers side of my 89 pathy 4x4 there is two items im not sure about....basically the little barrel that has a freespinning little plate and the big black cylinder with a few hoses going in/out it all just behind the drivers head light if anyone can tell me if these two things are 100%necessary for the running of the motor.....and also can someone give me a list of things that can be removed to add power and clean up engine bay?

thanks everyone. found 92 and 95 models in the local pullapart with fenders in nice shape. wanted to make sure first

i have a 1989 nissan pathfinder 4x4 and i need a new set of front fenders what all years will swap over?