You can have as many browsers installed as you want. The thing is that only one browser will have to be marked as default where all links will open. The need for portability these days is high and almost all Internet browsers have the ability to self-transform and configure into a portable thin application which is stored into a single folder. To make it a hidden browser, you just set the properties of that folder to hidden and you get what you want: a browser of your choice with your own settings stored into a single folder with hidden capabilities.
