Why u not driving the Euro anymore? :O
I think A Current Affair or similar program here, have tested the HiClone before. It showed a positive result actually but they concluded the effect was minimal, although measureable. At least its not a complete rip-off like the Fuel Polarisers, which were tested at same time and did not have any result.
Personally I've used HiClone before in a 1.8L Lancer. Couldn't really see any differences in power or economy... but might have? Don't know!