New
#20
I just re-read your question, and to be clear, you can run the preview and still "have my regular Opera and the Opera next side by side, same for Firefox"
It'll just overwrite your current Internet explorer files, and may even set itself to default browser, but you can obviously change it back to what you want. It's just that instead of having IE9 as you IE browser, it'll be 11 instead.
Hope that clarifies.