My '83 TR uses the same DS header (different years have different numbers because of differing heat shields, but they are the same otherwise). When it cracked, I replaced it with a '79 DS cast iron manifold (Turbo and NA are the same). This cast manifold may be a bit heavier, but I doubt it will ever crack and it has the same inner dimensions.
I pretty sure the crossovers interchange from 83/87 as well.