If one's personal minhag is to stay silent during the chazan's recitation of kedusha in the repetition of the 'Amidah (except for "kadosh…", "baruch…", and "yimloch…", which are recited in all minhagim) should one still keep this minhag when many or or most in the kehila recite all of the kedusha out loud?
For example, many recite the preface ("nekadeysh…" on weekdays and "na-'aritzecha…" on Shabas) and the passages between responses ("le-umasam…" and "uvdivrei…" on weekdays and "az bekol…", "mimkomcha…", and "[echad] hu Elokeynu…" on Shabas) which in German custom are only recited by the chazan. (A source for this is Rabbi Hamburger's Shorshei Minhag Ashkenaz, pg. 66.)
I figure remaining silent isn't so noticeable or disruptive to others so shouldn't be a problem - less so than reciting the entire kedusha out loud would be in a Ashkenaz shul where the kehila only said the responses.