Tyroneus

Got an '00 OB w/ EJ25 Ph2 engine. Bad HG problems - about to go onto 4th set of HG's. Thanks to SOA they extended warranty to 100K. Since prior repairs including upgraded HG's haven't fixed the problem worth beans - want them to replace engine. Understand that the EZ30 and 05 and later EJ25's don't have the HG problems. How difficult is it to swap an 01 or later EZ30 or an 05 or later EJ25 into my 00 Outback sedan? Thanks