Practically every Subaru part mates up to practically every ther part. You will be fine with your '00 engine, 90% sure. Subaru did make changes to the engines over time, but when it comes to physical mounting and stuff, it's all the same. From '97 to '00, they've done headgasket revisions, gone from a DOHC head to an SOHC head (the SOHC's better anyway; flows better and the torque comes on lower), and for one or two years ('98 and '99) tried adding two more bolts to the bellhousing to better secure the tranny. I seem to recall that they converted from a MAF to a MAP in '00, so you'd need a MAP sensor and an '00 ECU. That may have been in '01, though. Just do your homework. I suggest poking around NASIOC some. I've learned mostly everything I know about Subarus from there or stuff linked there.