Hi, I have a leak on the rear of the cylinder head. I've attached a photo of the pipe where the leak is. Have anyone repaired these before? Are they pressed into the head? Does the old one have to be drilled out?

 

Evo 5/6?

It is pressed/bonded(some sort of adhesive) into the aluminum. You should be able to grab it with a sharp set of vise-grips and break it free.

Once you get it free you could tap that hole and put a threaded barb in its place. Thats a good time to eliminate the throttle body heating circuit.