If I had the choice between fixing an old, used VG30DETT for 500 bucks, or getting a newer J-Spec one for an extra 700 dollars; I would go ahead and buy the other motor. Since you're looking for a project car, you could tear down and build up the original one while still giving ricers a run for their money. And it's always nice to have the peace of mind knowing that you always would have a ready stock of parts if you needed them.