[Koryak]

between 89 and 93 Octane Gas. I can not. I switch between a tank of 89 and 93 Octane. I know the computer will automatically adjust but honestly I have as much black carbon on/in the tail pipe no matter if I use 89 or 93 Octane. I even put one of the 100+ Octane Boosters snake oil bottles in the tank no difference. Pick up and idle is the same. So what is you reason to spend the extra cents per gallon at the pump?

I wouldn't expect any difference between your choices. The problem in the US is what additives a Top Tier gas retailer really uses. If I ever see a pump advertising the fuel contains additives for direct injection I'd buy their product. Good injector cleanliness will keep the tailpipe soot down, fuel economy and power up more than high octane