That's a strange thing to ask. IF you're a real poweruser, you're not using the standard release version of firefox, you're using the dev, beta, or nightly vers

That's a strange thing to ask. IF you're a real poweruser, you're not using the standard release version of firefox, you're using the dev, beta, or nightly version. In which case you have all the power you want and you can install literally anything --no matter how insecure or horrible it is-- by opening the add-ons settings, clicking the gear, and selecting "Install Add-on from File".