Got it now, BIG thanks to Samuel, whichever nick you go by here!

Edit: Hmmm... there's another music file I'm looking for, but I doubt anyone can help me there. I used to put it into levels I made with "ET's Planet 2 version3" back in uhh.. 2001 or 2002 I think. The instruments reminded of "Regret.mod" (which came with Renko's Battlepack 2) and "Mechanism Eight" from Unreal Tournament.
It sounded generally heavy/evil I think.
I wish I still remembered the melody... x.x

So, if there's anyone who has a file that sounds like described up there, please let me know, post the filename here or something. I think even that already helps.

.. I feel pathetic :P