Higher octane fuels will have no effect on the overall fuel map on the ECM - unless the engine was running poorly prior to this. Easiest way to improve on ET is to drop weight in the RAV4 - less weight, instant improvement in time. Automatic transaxles makes it a little easier to launch - just don't do it too early when you stage, no sense excessively heating up the fluid. Stage deeper in the lane (you'll learn this after a couple of times) - will get you a couple of tenths. Reducing unsprung weight and running better tires will help get the most from the launch (traction) and reduce inertia. After this - bolt-ons/internal mods/etc. - all depends on your budget, time, and goals.