Can I say that "I'm a believer in preparation and so are you." or should it rather be "I'm a believer in preparation and so you are."?

Thank you.
The "so" tag requires subject-verb inversion. It's "so are you".
And so are you.
And neither am I.
And you are too.
And I'm not either

So (and other) tag clauses often invert subject and object when they show addition.
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