hi Mark, apologies for not replying sooner, BP Ultimate for many reasons, most outlined in progressive posts. Just a note though, I filled the old banger, the shopping car, a Nissan Skyline 90 model (RB30 efi) one day at a local Shell Optimax outlet and nearly destroyed the engine, would not pull uphill, pinged, ran on and other rubbish. I challenged the output servo and would have taken the issue to the limit but for the lack of time and resource! Mixed fuels are the order of the day unless you connect with a servo of high integrity. Hope we can all find one in our local area wherever that may be,,,, All others in my area seem to be on the level but, unless we all have the knowledge and resources to keep these guys honest, who knows what goes into the tank!!!!???: Cheers to all from JB.