ej257 short block with ej251/252 heads in a legacy

Hey all,
I own a 00 BH LGT wagon, I acquired a ej257 b25c sti motor. I know you can bolt up the heads to the block.
But what crossmember should i use?
many say use an sti one, but i feel like it will not fit an a legacy bay.
also what parts do i all need for forced induction? here is my list currently.
uppipe
downpipe
BOV
Intercooler
fuel rail
injectors
walboro 255 fuel pump
sti water pumper
sti oil pan
Tune