Golf 5 1.6 FSI 2005 lack of power, poor on acceleration

Hi
I have purchased Golf 5 FSI 2005 3 months ago. And all I have got it with this car is trouble. It is my first german car and probably the last. Mechanics who connected VAG computer have told me that there is problem with fuel sensors. After spending a few weeks trying to trace it, it turned out to be High Pressure Fuel Pump which had worn tip. I got a replacement from a local scrapyard and fitted it with a cam follower which was not originally in my car. Car felt better and revs were more responsive but it was still lacking power and smoothness. Therefore I also replaced in-tank fuel pump. I did tested fuel pressure afterwards and it was around 3 and 4 bars in the speed range up to 35-40mph and above 40mph it dropped to 2.5-2.7bars - STRANGE?
Anyway, I have been told by some mechanics that there is no a problem with this car whereas others have said that it might be worn clutch, damaged cam chain tensioner, cam chain itself, even ECU.

As I am quite lost, I would like to ask a member near Stockport, Greater Manchester with a same car GOLF 5 1.6 FSI to let me test drive their car. I would pay for any petrol. And also that member could drive my car as well, to help me understand what is going on with it. I simply need to know if that car is driving as it should or is there any underlying, hidden problem with it.

Regards