Sir G C,
You say that you get 7% better fuel consumption in your VW. Better than what? Better than you got 5 years ago or have you made a recent scientific comparison? I can get a much bigger improvement than 7% by easing off on my right foot during any journey.
Whenever these fuel catalyst devices get properly tested by motoring organisations, they never seem to perform as advertised.
Talking of which, your post seems to be a poorly disguised advertisement, the likes of which are banned on this here forum.
