I have a corsa 1.2 16v sxi on a 57 plate. Unfortunately the head gasket went on it. I took it to a garage and I was told that the head gasket can be changed but there is a risk it could happen again as the head may be damaged? I was consodering getting the engine changed but I noticed there is a z12xe engine and a z12xep twinport engine. It has 79bhp, can I tell from this which engine I have? Is there anything else I have to consider when changing the engine? What is a reasonable price for a 1.2 engine? Any replies will be appreciated.