I dont think your physical reactions can be increased too much, your body and muscles have limit, but I think you could increase you thought processes to amazing speeds to where its almost like things slow down a bit

isnt that what autism (however you spell it) is? a heightened brain activity, thinking at super speeds, the average person only utilizes about 2% (or is it 4%) of their brains, if you could learn to utilize more than that stuff would seem a lot slower I think