Should you have checked in to my comments on my last post, you'll note that H1202 posted a most eloquent , and investigative, response to my off the cuff question about the appropriate plural of the word Prius.
Since O tends to have a fun time with language gymnastics, as much as an almost-4-year-old can, she suggested that I ask for his thoughts.
I have to say she may be a little disappointed, though I kind of expected his response.
When he sees a bunch of grown human males, it's "mans"...I think at this age all gets the plural "s" treatment. So I will be sticking with referring to them as our Priuses.