higher octane can be beneficial or required depending on many factors, tuning that can be easily varied today is a biggie + anything turbo'd can really pop with higher octane + the correct tuning involving boost, fueling + timing. look at the goapr site a top tuner for VAG aka volkswagen audi group vehicles to see the real effects of proper tuning with higher octane. manufacturers tune conservatively for longer engine life hence the blown warranty due to higher power outputs that require many upgraded parts to handle higher power safely with longevity!!