looked under several years/models and it seems the header (y- tube to first flange from cylinder head) is near identical on every subaru. Smashed mine good on the first drive after 4 years of sitting still,  was hoping the trip to the junkyard would be easier knowing this part was like the fuel filter, and was almost unchanged throughout ej25 history. And yes I know the filter has been around since pre ej25

 

yes, all ej25 have a dual port heads.

so the y-pipe will fit.

but around 04 they did make some changes,

so stick to 96 - 01.

 

you can also use orther y-pipes,

legacy 90 - 95 ej22

impreza ej22 93 - 95

impreza ej18 93 - 97