I agree with Pinky.
Imax 2 is fun, and I only modify about 1/4 of the moves (and not too much at that: just not jumping as high, for example).
IMAX 3 is way over the top in terms of impact for me. I modify almost all the blasts, sometimes changing them so completely, they don't ressemble the original move. The choreography is more complexe, and I think it's also not as well cued as some earlier workouts (including IMAX2) , which makes the choreography seem all the more difficult.
I do both IMAX 2 and IMAX3, but end up doing 2 more often than 3, and enjoying it more. 3 is kind of a "I guess I should do this one for variety" workout.