That's it, mate!!!
I was looking for such an addon for a very long time. It's so easy to use and it makes surfing a lot more convienent. And the best: it's not to difficult to be extended with new links! Just go to any site, insert any term you are searching for, copy the following link, insert it in the empty box at the bottom of the settings, replace the item you were looking for with a "*" and press save ("Anwenden"). Sometimes you have to restart FF.
Well done, thumbs up, five stars.