That is a hard course, but some tips can be offered. Try a Quick Run and go at it slowly. Let go of your gas while taking sharp turns, and practice makes perfect, and practice not falling off the edge. Make sure if you get a Mushroom, you use it in a good spot. Take it slowly at first, then you'll turn out like me, who can now master Super Circuit. Well, I can do 50 and 100cc, but 150cc is almost impossible! Especially if the guy in 7th place comes out of nowhere and passes you!
