The calipers themselves should work on both platforms, but you may want to double check that the rotors are the same size. If they are not, then just put the 04 Forester rotors on too.

Quote Originally Posted by prodriver1 View Post
looks like subaru made a change for 02' and up, don't know if its a mounting change that would make bolting them up a problem or if its some internal thing that doesn't matter like bigger pistons or something, the parts # aren't the same, but its like a 20 min job to fully swap and just see if it works.
The difference between 00-02 and 03-04 is the size of the rotor. The calipers are larger to accommodate the larger rotor on 03-04. There are no mounting differences between them.