front diff. replacement????

[newkid17]

ok so i found out (thanks to you guys) that my pinion bearing in my front diff. is bad... so i was wondering if it is easier to replace the whole front diff. or to replace the pinion bearing only? and if i was to replace the whole front diff. how do i do it. does the tranny have to come out?is there a certin front diff. that i would need or will anything out of a subaru fit? i know that the diff. comes befor the tranny so i am thinking that there is enough room to squeez the front diff out without taking the tranny out. i really do not want to take apart the front diff. just to replace the bearing unless that is alot easier..? i could really use some of your guyses expertees.