Don: I think the vibration affects only a small fraction of the SR22’s. I have never had a vibration problem and I think that is the majority. Also, I am not certain, but I think that the kit that Cirrus put together has solved most of those aircraft that have experienced vibration. There may be some unresolved vibration problems out there, but I am not sure.
At least one SR22 has required a prop balance to resolve the vibration. I haven’t needed that either.
I think most of the vibration problems relate to some part of the engine or a piece attached directly to the engine coming into contact with the cowling. I would surmise that the SR22 is essentially free of vibration problems, although some particular aircraft have had instances of vibration. I also think that the “kit” that is part of the vibration SB is the result of production line modifications to the part that was contacting the cowling.