Why don't you just name it S.L.O.W. without any other words? Does it need to be two words? If it does, maybe a second acronym would be cool.. something like:
S.L.O.W & L.O.W.
Where L.O.W. stands for something that represents you.
I may be alone on this, but I don't think Sexy Ladies on Wheels is a great acronym either. It's too blunt, and if you are all attractive, then it's information that's worthless. A woman who calls herself sexy isn't as attractive as you may think. Maybe you should find an acronym that describes your taste in cars (flashy vs simplistic, show vs go, straights vs. curves, etc.) or aspects of your personality (aggressive, bubbly, etc).
In the end, it's obviously up to you.. but I think a name that better represents what you stand for and who you are would be best. There are plenty of attractive women who are into cars. What makes you different from them? What makes your group stand out?