I have installed a surbo and it works fine for me. Definately
can feel the thing working and the car feels more powerful. Fuel
comsumption wise I am recording a 10 % improvement after 2 tanks of
trials.
I think the Surbo does function as explained in their website, but
for it to work in your car, you need to ensure 2 things :
1) The engine has to be air-tight .... so get it installed by a
authorized mechanic.
2) You need to "activate" the "turbo" using the throttle control
during acceleration .... once you get the technique right, can feel
the power surge.
Finally I think this device works best if you are the type of
drivers who have a heavy right foot. btw, there's a refund policy
and the installation can be reversed easily.