I used the Double Jump and Wheel Goat mutators for the Big in Japan achievement.
The Wheel Goat mutator freezes time and stops all of the moving obstacles from actually moving taking them out of the equation. You have to freeze time after you start the course and unfreeze it before you cross the finish line for it to count though. You use the cn_Y button to control time.
The first part of the video below shows where to get the Wheel Goat mutator if needed. The Whiplash course starts at 3:10.