At the risk of encouraging stereotypical responses....

I can't think of my W126 in anything but masculine terms. I am thinking of naming him, but I've only done that once ( Car was named "Damn Car" after the times when my girlfriend (later wife) would call my mom to see why I was late in picking her up, My mom's reply to the question always started, " Damn Car!.......)
The name for the W126 ( 300SD) that seems appropriate is " Wotan". For those not familar with Wagner's characters in the Ring cycle of opera ( could it be that any such uneducated persons exist here on THIS board?), Wotan is the King of the gods. What more fitting name is there for the king of cars?
I see most British cars, as well as all French, and most lesser Italian cars as feminine. Asian cars seem to have all character designed out so are gender neutral. Italian super cars are probably masculine, especially the one that grew from a tractor manufacturer--feel the testosterone!
American cars vary too much for generalizations. Except the pickups, especially diesel-powered ones; they have to be masculine!