Glx -- a long shot, but one of the most musically satisfying Goldmund pre's was an old one: Mimesis 7,1 (or,2, or whatever). Οther pre's (tube) I have heard w/ Goldmund & particularly liked were the CAT Ultimate & the big Octave (a german product).
However, I would look into source equip first & keep the BAt for now. At your system level, it seems that Mikelavigne's (& tierguy's) latest digital combo would offer very competitive performance. At a more reasonable investment level, you may consider the new A Aero with sacd or a Lindemann. There are many other choices of course which I haven't heard. Cheers!