Would it be more economical to overhaul a mazda or just replace the engine?

What is your question?

So the mechanic found a used engine with 30k less on it and told me he could do it for 1100, but what about an overhaul? Are those successcul in mazdas or are they just too tempormental to work on? I haven't had a lot of luck with mechanics lately. They seem to be working me either way.