Being a thrifty Northerner(?) you may be able to hack-repair an otherwise good coil pack with a harline crack. In theory you dry out the coil pack ,clean it so you can identify the cracks and seal with epoxy. There is a Youtube video but....
" Good used" may be an oxymoron in the case of coil packs from a breaker? Try EBay U.K.?
If water has penetrated the cracks, here is what happens:
http://rennlist.com/forums/996-forum/902647-just-replaced-the-coils.html