The Miata is the most common vehicle to be used as a race car, according to the SCCA. So it's definitely one of the coolest out there, regardless how effeminate it may seem.
Also, all cars are girls. This is just a fact of life.
Interestingly, the whole "vehicles are female" thing comes from the fact that ships are, in proper English, referred to with feminine pronouns. There are a lot of grammar rules specific to ships, for some reason, and they're the only properly gendered objects in our language. They're also the only non-literary things with italicized/underlined titles. And as long as you're reading this far, take note that you never put "the" in front of a ship's name, unless that's actually a part of the name. She's called Titanic, not "The Titanic."