Having read a few reviews on here including yours. I think the difference is very noticeable.
I have had my kit fitted for around 24hrs now. And i can definitely tell the difference. The torque increase can be felt (be me at least) quite noticeably. 17bhp extra will never make a huge difference, but it is one I am very happy with. I hoped not be disaappointed, and I wasnt.
Sometimes peoples expectations of such a product are too high. Mine weren't. Thus I am extremely happy with it!
Also hearing the turbo whine (with the windows down) is a nice bonus.
...Mad