[Gozar]

эти плагины http://webpack.github.io/docs/list-of-plugins.html идут из коробки

да.

webpack.config.js

var webpack = require('webpack');
module.exports = {
//...
,
    plugins: [
        new webpack.optimize.UglifyJsPlugin({
            compress: {
                warnings: false
            }
        })
    ]
}