IE /st/ > Etruscan /z/

[Adolfo Zavaroni]

I think that Etruscan /z/ in most cases corresponds to IE /st/ both at
the beginning and in the middle of a word. According to this suggestion
the shift should be attested in words of the VIII-VII BC, so that it was
presumably actual some centuries before the first Etruscan writings.
I do not want to say that Etruscan is an IE language, but just to fix a
correspondence, since undoubtly the Etruscans, if they were not cognate,
had to borrow many words from the IE peoples during their secular  touch
(e. g., all the 7-8 etruscan names of vases are borrowed from Greek and
Italic dialects, according to a common agreement).

I should want to know if :

1) the shift "st > z > s" is attested in other old languages, besides
Celtic (Stirona > Zirona > Sirona, Bret. sterenn, W. seren "star" etc.
and Italic words (Lat. satelles, saucio, sileo etc.);

2) or my hypothesis is unreliable for some reason.

Thanks
Adolfo Zavaroni