That's right, the manual recommends 89 Supreme or higher.
I had my car for 7 years now and been using 89 octane. every 5000km or every time i change the oil i usually put in a fuel additive that cleans the fuel system. Valvoline Syntec fuel additive $19.99CAD. The only thing you should keep in mind is to never leave the tank empty so that dirt won't get into the system. In terms of performance, I find no difference in using 89 or Sunoco's 94 octane. I hope this helps. Oh and another thing, use brand name gasoline. Some cheaper stations uses lower octane levels which will cause your engine to knock which in the long run leave you with costly repairs.
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