87 octane = 87 % octane 13% other chemicals..not sure what they are... leaded gas doesn't work liek that becuase the "lead" that it uses increases the rating but doesn't actually add octane, whcih is why I don't see how you can have unleaded +100 octane gas.
a random noob once said: "I think its great that I can make a civilized post among you greater life forms and get my breasts ripped off by savage milk craving z people."