Jafant, I own the BAT VK40 solid state pre but I've heard everything up the line including the REX II and I'll be quite honest, the air is so thin at that level that it's hard to really hear a discernable difference....I mean if you really listen carefully to the same song repeatedly for hours on end and then switch preamps you may notice the slightest bit of additional warmth or bloom coming from the REX but it's something that you'd have to condition yourself too over countless hours of listening. It's not something your wife or girlfriend will notice by walking into the room and. Saying "wow! That sounds so much better! What did you do!!?" If yourlooking for that type of response, take that $20k and buy her a nice diamond!! IMHO , the difference doesnt justify the cost and I happen to be a die hard BAT fan. As always listen for yourself but I dont feel the means justify the ends...
Good luck!
Good luck!