Is that the FSE power boost valve?
I put one on my old Uno Turbo, it replaced the standard fuel pressure regulator, it had an adjuster on it which I had to fiddle with - when I first went for a drive the performance was quite bad and I had to adjust it a few times until I got to a point where I thought it was good enough.
The car was later setup by a proper tuner - I think he adjusted it properly as the car felt much more powerful when he was finished.
So no, I dont know if they are any good (I have a suspision they are crap) but if you do get one I would reccomend getting a tuner at a rolling road to set it up for you.