Oversteer & Understeer
Find The Limits
A good race driver wants to find the perfect amount of slip angle for every corner. So if you are asking if drifting is the fastest way it all depends on how you define drifting.
Drifting usually means huge amounts of oversteer with full lock countersteer. So in that case, no- drifting is not the fastest way through a corner.
Oversteer and understeer is something that you just have to learn to deal with if you're racing. Finding the limits of your tires and getting to know the slip angle is really what the quest of a racing driver is all about.
When you first start to explore these limits of oversteer and understeer youll find yourself amazed at how wrong you are at judging corners. But improvement is near, just keep on practicing!
I have only touched upon the surface of this topic. Grip racing goes pretty deep but this article will help you understand it all a little bit better. If youd like to learn more about the subject I suggest you pickup a book that involves racing dynamics.
Theres a lot of info on the web too. For an elaborate explanation of racing dynamics I suggest to read the physics of racing from Miata.net. Beware though, these documents are quite analytical with a scientific approach!