well, its an item that swirls you air from your intake so there is some amount of compression. Kononnya give more performance and better fuel economy.
Soil.. whut car are u driving?
Basically, the surbo does gives a mild performance for cars bellow the 1.3 category. I used the cyclone version on my iswara and after i took it out i can feel the lag-iness. Now with my carb 1.0 sohc, i can feel quite an efficient amount of power increase. Although not a lot, but honestly its there. read the FAQ in the surbo site in more detail to see what can be the causes of no getting no increase in performance and reduction fuel consuption.