This comes up all the time time.
I actually think the two are immutable.
You can't have one without the other.
Stylish people have a very particular ownership of themselves. They know what they love. See Daphne Guiness, Grace Coddington, Tilda Swinton. These women are stylish as fuck.
BUT, they are also fashionable. They are all very interested in fashion, and keep themselves current, by keeping an eye on, and being very interested in 'Fashion'.
I honestly don't think it's possible to be stylish without being fashoinable.
Fashionable doesn't mean fashion victim, it simply means, being interested in fashion and adapting current looks that fit in with one's personal style.