Tube amp for Genesis 500

I am considering going to tube amps for my Genesis 500. They are the front speakers for my home theatre and are presently powered by a Pass Labs X5 (250W x 4ohm)and run thru a Krell Showcase processor,but I want the tube amps for more musical stereo listening. Due to space considerations I would like a stereo/dual mono version with enclosure/cage for pet protection. Budget - 5K. Also, what are the pros/cons of self biasing? Any present/previous Gen 500 owners out there who can lend their expertise?
I used 2 pairs(4 units) of BATs VK 60s with the GEN II with great results. For Gen V/500, one pair will do fine.
One pair of VK60s can be bought used within your budget.
I use an ARC VT100 MKIII w/my Genesis 500's and they sound superb. You only need one, no need to biamp. You can find one used for well within your price range. I think two would be overkill!
I use ARC Classic 150s for my Genesis Vs. I was using the
CJ 2500 ss amp before and have found the ARC amps to give me everything I was looking for with these speakers. A more natural midrange and highs that don't cause me to want to leave the room. Also a sense of a greater presence and deeper soundstage.
By the way Nudell used ARC amps to voice his speakers.