Energy drinks will give you one or two good lights, then when your coming down there will be a sh*t light. If your wanting to go to the finals try to be a consistant as possible. Don't work on how quick you can be, but how consistant you can be. I try to have as small as possible variance between my best light and my worst light for the day.
I hear crack last for hours, only problem is your teeth fall out. lol.