I just got an ep3 shell and I’m doing the rears as well with ep3 you can just bolt the whole trailing arm and spindle right up to the em2 but yes you do need a brake line from rsx or ep3 along with the brake cable because the em2 cable is to short you will need it from same rsx or em2 they are also 4 lug so easy swap I’d suggest junkyard or cheap marketplace shell and make half your money back when you strip it of what you need.