You can download the MxStats desktop application by visiting MxStats and clicking download on the latest version on the right hand side of the screen. You can also discuss this application on the Wargaming official forums by clicking the links on the right hand side as well.
Moving forward the popular section of the site will mostly be populated with replays uploaded via MxStats. The home page will continue to show all replays as it does now, but your odds of being featured in the Popular section go up considerably by uploading via MxStats.
You will soon be able to search on Kills, Damage, Credits, and more from the advanced filtering as well. I hope you enjoy the new features, I’m looking forward to adding more features in the near future.