Just my .02 cents here but mine almost feels like they have pushed the timing envelope so far, that if your running 87 octane, the faster burning fuel is firing before top dead center causing the engine to fire early and kick back against the starter. My 14 has been turbo'd since new and never reflashed cause it has been always a turn of the key and start. My 15 last season was N/A and I only filled it up once with gas from the hauler which was 91/110 octane mix added to the 3 gallons of gas the dealer had in it and never did it. When I brought it home it was as close to empty as possible. To move it I put 4 gallons of 87 in it that I had in the shop and 3 times in warm weather trying to start it, it kicked back.