Off with the head, or engine out ????

[bob gray]

Hi all
I have a problem with the car burning oil in quantity ! when driven hard,I found a lot of oil in the intercooler so first thought is the turbo (right ). It has apparently been fitted quite recently. When I bought the car Ian said there may be some oil still in the intercooler
when the turbo went, I however cleaned out the pipes and intercooler. Further investigations revealed oil in the plenum chamber and the hose to the turbo inlet was also oily. ( I am assuming this could only come from the engine breather ) I did a compession test and all except no 4 were about 125 psi no 4 just about made 40psi. I would like the advice ,, is it best to remove just the head and investigate or bearing in mind the symtoms remove the complete engine and rebuild ??First senario is cracked head ?? worst is holed piston or bore fcuked.I was intending to take the car out for the winter and do a little bit of bodywork repair What would you advise

Bob