Mas Te Vale Que No Te Metas

"Mas Te Vale Que No Te Metas"

How do you say this in English??

This is very colloquial speech.

You are better off not interfering in this.

or

Don't interfere [like it's not of your business, your opinion is not wanted]

Better don't mess with me! Or
You better don't mess with me!

María

I don't agree with that. If it said Más vale que no te metas conmigo, then yes, because it is directed at you. But the way it is, it's like do not get into something that doesn't concern you.

What do you guys think about: "Go mind your own business"? I have heard/seen this expression a lot.

Yes, definitely...that sounds perfect because it is actually very colloquial and in tune with the original.
It conveys both meaning and tone.

Xóchi Xóchi se me ocurrio otra, qué te parece stay away [from this]...

I like stay away too, but I think it sounds "softer". Maybe we can use either one, depending on our mood or on the person we are talking to. Porque de repente te encuentras con cada gente... :-)

Buenas...

A few more colloquial options:

'You'd better keep your nose out of it'
or
'You'd better stay out of it'

depending on context.

Me encantan Cristina. Diste en el clavo!!

Holly Molly backstreet! Those girls have really gotten into an argument!!!