Like Charles, I havent heard Audion but have been favorably impressed by Viva. If youre concerned about claims that Viva amps are slow (Ive heard that claim elsewhere), all things being relative, I actually thought they were fast. Keep in mind that other factors could be involved - tube selection has a huge impact on Viva amps in my experience.
Im not recommending Viva to you Wylmars. Even if I heard them with the Westminsters and loved them, I would hesitate to do that - its too personal of a decision. But if you are seriously considering Viva, I recommend that you call Amedeo Schembri, the amps designer. I wouldnt be surprised if he knew the actual amps for sale.