On most cars, the timing can adjust according to the octane of the fuel. As can the tC's, so higher octane doesn't lead to any cleaner burn-off, or timing. Stick with 87 octane, and buy a mountain dew with the money saved .

 

I'm in California where gas is a total rip all the time. I spend near 30$ to fill the tank. I can get pretty good mileage out of my tC if I don't put too much foot into it. When I do a lot of fast starts and drive more like all the other A Holes here in SoCal, my mileage can nearly cut in half.

 

30 dollars??!! where are you filling up? good grief that's a lot of money. make sure you're putting 87 octane in your tank. if you want better gas, go to chevron or 76. chevron by my house in glendale is at 2.01 for 87 octane. my bro has a tC, and he doesn't spend that much money.

 

14 gallons multiplied by $2.01 still equals $28.14 which I consider near 30 bucks.