Kri’at Shema in a Whisper

As a speech therapist, I was wondering whether Kri’at Shema can be done in a whisper. In a whisper, the “z” sound is produced as an “s” and the “v” sound is produced as a “f” (and all voiced sounds become devoiced). Scientifically, this is because the vocal chords do not vibrate when whispering. Doesn’t one need vocalize to truly produce a “zayin”, “vav”, or any voiced sound, when saying Shema?

Reciting Kri’at Shema at the Very End of its Time

My shul sometimes misses sof z’man Kri’at Shema (=szKS) by a few minutes. The rabbi instructs people to say the three parshiyot of Shema before davening, but I usually go ahead to make Kri’at Shema on time and wait during the following beracha for the tzibbur to catch up. Is that an improvement and/or a perfect system?

Shortening Psukei D’zimra to Catch Up