91 octane is recommended, but not required. The ability of 87 octane to ignite at a lower temperature may actually even be ideal under light-load situation's to reduce fuel consumption.
'15 IS350 F-sport Ultra White/Rioja Red
'09 E90 M3 7-DCT Interlagos Blue/Novillo Silver
[MS Pullies|K&N drop-in|Test Pipes |Evolve Stage II tune|Evolve Servotronic Map|Evolve M3 GTS-DCT file]