what type of engine do I have?

99 ford ranger.
Rear wheel drive.
4 cylander, 8 spark plugs either side.
On the rear, hiding some of the drivers side plugs is an air intake manifold.

Two reasons:
1, so I buy correct parts.
2, so I know how to change the spark plugs, they are a nightmare, do I really have to completely rove that metal manifold or are there special tools?

Sorry, photo file size is too large... :-(

So far, there is no photo.