to save time, i did it before.:p
i did not take cal 1 and cal 2 (read it myself) before i took cal 3, and i did not take any statistics course before i took the classes using Statistical Inference by George Casella (Author), Roger L. Berger (Author) and econometrics using Econometric Theory and Methods (Hardcover)
by Russell Davidson (Author), James G. MacKinnon (Author). Apart from A- from econometrics, I got A in other classes mentioned above.
So I would not bother to suggest it if 1) you have confidence in yourself 2) your school allows you to take any courses without its pre-re and 3) willing to take the risk for any purpose
it does save time~