Don't worry about piracy for old WoW clients. The server itself is already a pirate. If Blizzard cared, they'd come after the server in the first place, not forum links to where you can get clients. Also, since there's no legitimate way to acquire these anymore, you basically have no choice except to pirate it. You could buy old discs that managed to survive 10 years, but Blizzard still won't see any money from that second hand transaction, so you may as well have pirated it. You'd also have the extra work of patching it up to a specific version. You can't use Blizzard for this as they will patch it all the way up to the current retail version, ruining the client. You want 1.12.x, and nothing newer. Blizzard, in addition to not offering/selling older versions, will also not give you the option to select a specific patch to stop on. You'll have to use third party sites to pick the patch... You may as well just pirate the 1.12 client and save yourself all this trouble.
As for the Feenix client, I tested it and it works fine for every server I tried connecting it to. I don't know why people say it's been altered. It's enUS, although I don't know any differences between them other than the fact that the US version includes a randomize button under the name creation. Perhaps the EU client supports more languages?
1.12:
http://www.wow-one.com/forum/topic/135- ... d-install/If you don't trust this, you can use that certain "swedish" site, but the second most seeded torrent is the exact same torrent that I just linked(It's what the Feenix thread links). The highest seeded one is from VanillaGaming. The only real differences I've noticed is that the Feenix client is enUS, while the VG Client is enGB. Again, I don't know if this matters at all, pick the one you like. I connect to all these Europe servers just fine with my US clients. I've been running the Feenix enUS client the entire time I've played on Nostalrius and haven't seen any issues in doing so. After you get the client, just use the Nostalrius realmlist, and that should be all there is to it. The client doesn't even have Feenix realmlist info in it, hence why the thread tells you to put that in(so much for being "altered").
This is another that I help seed, Feenix 2.4 for BC. I help seed both of these on my BT, allowing up to 1MB upload.(Although the VanillaGaming torrent is actually better seeded even without me on it)
http://www.wow-one.com/forum/topic/139- ... d-install/