Which is the best high end passive power filter?

Hi members, I am currently seriously researching the best passive power 8 point filters & would like to know firstly if there is a passive filter which unquestionably improves the sound of high end audio systems without strangling dynamics, or imparting a sonic "signature" of it's own? And secondly, as I live in Australia; is either available in Aust-spec, or is sold by a company which is likely to offer the board in that spec?

An obvious front runner at the moment is Shunyata's new Hydra 8v2 which offer the Hydra in Australa. I have heard the new model 8v2 is slightly better than the previous Vray which is a big wrap.

I should say I am sceptical about power filters. An audiophile friend of mine who happens to have owned a hifi store in Australia for more than 25 years said he never heard a power filter (in Australia) which didn't have a negative impact on the sound, including some very high gear including (from memory) a Burmester active filter, so I would need to be convinced to take the plunge.

So is the new Hydra 8v2 the best option, or maybe even a stretch to save for the new Vray v2?

(Thanks in advance for your ideas)