Question: ngu how to spend exp?
Answer: Get your energy speed up to 10, then get your energy per bar (now called just Energy Bars) up to 2.
Now get 12 SPEED and 3 EPB. ( ... 
Welcome to the golden ratio. ... 
Keep that ratio of 4 speed to 1 EPB.
You will want to keep that ratio while pushing your speed to 50 and your cap up.