i never used discogs, because i don't know how, but ive heard you can find anything there, and i dont have many manson items, i just started my collection, because thansk to where i live i can't ever find manson merch anywhere, and plus i cant buy things on the internet because of the shipping thing! some very rare times they ship it to my country but.. its really hard, i do what i can..
Discogs is an amazing tool. You can find most of the variants of a release. Not just Manson. Make sure the have a profile, then you can build your online collection and make a great wantlist. Where do you live?