That would be my guess, I just left my rear disks on my '98 EX. If you know somebody with an Si, you can take a look at theirs and visually compare it to yours, but I'd be suprised if they're physically different shaped. You can also take a look at their MC and see what size it is (it's cast into one side of it). I would just leave the MC and booster alone, grab the prop valve if it looks like it will fit and go to town.