The manual says 87 is recommended and that you should NOT go BELOW that, some areas have lower octane gas as their "regular". It also says that if you use higher octane gas, you'll benefit with slightly higher performance.
2012 SGM SEL Sedan 303a w/o Nav | Job 1 built 6/2011
FSWERKS Cool-Flo w/ ITG Filter | FSWERKS Stealth Exhaust | 17x7.5 Axis Sport XMX Graphite wheels
Sonic Crew #28 | Rally Revolution #117