gas

higher octane doesnt make too much of a difference, just go for 87

personally gas is how much you want to spend. example. you get 91 for your your engine will burn cleaner and burn the gas fir a longer distance but its more expensive on the other hand if you buy 87 it is cheaper but doesnt burn as well.. now on a higher performance engine like my matrix xrs it need 91 or high to be fuel effecient cause of its high compression. so in reality if you pushin rpms or a turbo you might want better gas but if its the commuter car with a grasshopper motor jus put somethin in to keep it goin

octane is resistance to self combustion under pressure. Higher octane is for higher compression engines. unless you are driving a ferrari or motorbike, any difference between 87 and 92 is in your head. In fact studies have shown 92 to produce LESS power in lower compression engines.