Many of the chips available for older model BMW's that run 87 octane modify the spark advance so that it can take advantage of 91 octane. The chips we have in our E46's are tuned by BMW to take full advantage of 95 octane (however, the computer will automatically detune the software if it figures out you aren't using 95). I don't know of any chips that take advantage of 100 octane. But, you can mix 100 octane with 91 octane to get 95. I do that when I go to the track.