General rule is higher compressin = higher octane fuel to prevent pre-ignitin knock, etc. This can be offset somewhat by the ECU retarding timing, but at the expense of performance and can still be a problem under heavy load conditions. This be the rule that applies.
Forget about boost and hot cams and stuff, that's all for tuners and racers which is an entirely different topic.
http://auto.howstuffworks.com/question90.htm