How i can do unit setup in wings so i can set the metric unit to meters?

[micheus]

There is not option dialog for STL exporter, since most the time any resize can be made in the 3D printer software.

But, because time in time someone ask for units/scale I'm going to propose a change to the plugin adding that option. Once you define the scale first time it will be used as a preferred one for further exportings. I hope that can help a little.