Where are the plugs

Stupid question I know. But where are the spark plugs on a 2000 jeep cherokee with a 4.0. I need to change them and the wires but can't find them. I am sure I am blind, but please help anyway.

THanks

Stupid question I know. But where are the spark plugs on a 2000 jeep cherokee with a 4.0. I need to change them and the wires but can't find them. I am sure I am blind, but please help anyway.

THanks

Never mind, I found them and changed them. It looks like the entire thing that is above them is one piece (coils and rubber boots for plugs). How often does that thing need to be replaced, and how much is it.

thanks