Your questions about the FTP kit should be essentially satisfied with the answers in the question you posted on the forum here. Beyond that, the maximum power that can be obtained from any product using the FTP is what the "American" version of said product would obtain- the point of the FTP, as outlined, is not a "maximum power" situation but a "save pumps" situation.

Also, your email came in two days ago, your telephone call about 2 hours ago, served on top of the answers provided here in the last couple of days and I think the assertion of "fail" might be a tad off the mark.

One thing people need to understand in general is that I will not get into a five email back-forth with paragraphs of information and hours of effort for information that can be obtained in the online forums rather easily- with a more rounded opinion from numerous people- not just my opinion, which is by default always going to be questioned as a result of selling the product.

How does this relate? When I say "you will get, maximum, the same amount of power the US version of the product outputs" the next question is "why isn't the valve modified for flow and so on" and then the response would be "because unless using a .22 caliber 24" barrel and adding other parts, valve flow improvements will gain you nothing..." which then begs the question "what do you mean/why is this" and so on ad infinitum- all of which can be found in the forums. An encyclopedia of knowledge is available in the airgun forums- and we are not in a position of re-writing the encyclopedia for every email request. Sometimes people either need to go looking, or take a bit of a leap of faith and do their own experimenting.