Word of warning - 91 RON E10 isn't normal 91 RON petrol with 10% ethanol added, it's petrol with 10% ethanol added which bumps it UP to 91 RON. When they first released E10 it was 94-95 RON (based off regular 91, because the ethanol bumps up the octane rating), so if 10% ethanol bumps the RON rating up by 3-4 points then I shudder to think at what crappy brew they use which requires 10% just to get it TO 91 RON. Personally, I avoid the stuff like the plague. You get next to no savings from it (even though it's cheaper, you use more), and on a high-compression engine like a 2ZZ in a Sportivo I'd be using 95 minimum, if not 98 (EDIT - realised too late that the OP means a Camry Sportivo, not a Corolla...). I'd even hazard a guess that the E10-compatible sticker is referring to the old 95 E10, not the new 91 E10 (the system can handle the 10% ethanol content, but not the low RON rating)