Is 5 Watts enough for Horns ?

I have Trio 2.2 (8 ohms). I have used Viva Aurora (845 set)monos for three years. Mine has the transformer input. This is a must with horns, the tube input version is too noisy. Mine is dead quiet. Recently I tried a friends Wavac 300b. Enough power. The 845's are just totally more effortless though and better balanced (very extended at the extremes). I also have now a Yamamoto A-08s (45 set). It is ok sounding in comparison but not as good as the Viva. It is also enough power. With trios you have a speaker that is capable of effortless dynamics and presence. You will not get this from a 45 set. With the 45 set the trios aren't that much better sounding than dynamic speakers. I would go with a minimum of a 300b or maybe the Art Audio PX-25 I keep hearing so much about. My 845 IMO is much better than these and not just in power, all other areas too, very clean sounding. I have not heard the px-25 in my system though. 845 amps are very expensive to build and if one is chosen it must be of the best quality or I would chose something else. There are only a few manufacturers building to this quality. I have heard many comments saying the 845 tube is not an audio tube and can't compete with the lower powered tubes. Yes, for many lower priced 845 amps out there. But when it is built right, and top quality, IMO it is hard to compete with it.