If your local fuel is that bad, you could run a 91 octane tune using 93 octane fuel.I hope the turbo install goes better! Winter gas caused -2 to -3 corrections and 2 gallons of E85 really didn’t help me either. That is how bad it can be and winter E85 in NC is E70. I tune 93 in winter but don’t drive the car much and if I have issues I run the stock tune. Then back to E30 in the spring.