Best bet is to follow the manufact's recommended octane. Going higher is (usually) just feeding the pockets of the oil folks.
REAL tuning (chipping/cam timing adjustment/engine mapping/etc) could mean you need ever-higher octane, but a REAL TUNER knows what they are doing and can provide DYNO results as proof.
A basic stock set car... go with manufact recommendations.
Am glad you enjoy Enjoy the Music.com and appreciate your continued support :)
Keep the shiny side of the car up and as always...
Enjoy the Music,
Steven R. Rochlin