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.
Once upon a time I had:
2012 SGM SEL Sedan Job 1 BD 6/2011
FSWERKS Cool-Flo w/ ITG Filter | FSWERKS Stealth Exhaust | 17x7.5 Axis Sport XMX Graphite wheels | Eibach Sportlines on Ti Handling Pkg bits