Prefer to keep her, but I don't have the funds to buy a new engine for $6k so:

Do I buy a rebuilt engine for $4k?

Get a used 01 Axiom engine for $3k with 50k miles on it and risk having the same problem?

Or, doing an engine swap?

If so, which engine would be most compatible with the least amount of modification, and has anyone been successful in doing this?