I've noticed in my linear I've been pretty bad. I've been running on quarter tank like all the time, being el cheapo and putting in 87 or 89. occassionally 93 but it felt like overkill. Anyways my whole point was I put in 91 octane from sunoco and i noticed a HUGE difference in car over 89. Should I be putting in 89 or 91? How big of a difference is it?