Sorry for my english.
Is it safe to install?
Yes. But it covers a good portion of your screen. That can be pretty annoying. There is already enough screen clutter. However give it a try, maybe that won’t bother you.
I have the other part on my iPad and use that.
http://us.gw2stuff.com/en
Open the site in your brower and alt/tab between the game and site.—-simple and easy.
Having it running on another device is ideal though.