Its a diffrent octane system for sure. We use 95-99 RON gas. The quality however is better than in the US.
In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States, Canada and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 8 to 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "regular" gasoline in the US and Canada, would be 91-92 in Europe. However most European pumps deliver 95 (RON) as "regular", equivalent to 90-91 US (R+M)/2, and even deliver 98 (RON) or 100 (RON).
Z-Engineering says that 0.9-10 PSI is max on a standard VR6. HGP uses 8.5:1 on their VR6 turbo system over 10 psi. And they are THE VR6 tuner So I cant see how you could manage to get 400hp and not lowering the compression.
However, still waiting for C2 for a respond on my problem.
Calling them has not worked out, I know they have really busy days sometimes. All the pins are exact the same on US/Euro ECU. But are the censors inside the ECU the same?