in the end the choice is up to you.... im not sure how car savvy you are but a direct swap wouldn't be nearly as difficult as rebuilding the guts of the engine. I would suggest taking it to a local mechanic and see if you can get a quote from him.... then price that against a few engines you come across.. then make up your mind.

+side is if your doing the rebuild.... and you wanted to build a proper beast, you can, just take your time and do everything right.

are you throwing any codes?