Any of the 5vz can have head gasket failure I have a 2001 that I replaced a head gasket I did one on a 98 and a 97. I think the head gasket will fail at some time at about 220,000 give or take 20,000 your mileage may vary. The only thing you can do keep the cooling system serviced when it does happen take care of it right a way it will only get worse. Don't wait you will end up overheating the engine causing more damage. The JDM engine is a way to go but that can be a crap shoot. If it's only a head gasket I would not go the JDM route but I would make sure I get the heads resurfaced and the valves cut.
