It seems like it's harder to control on the newer WRX and STI then my '09. I don't like it personally either because it feels like it takes away from the feel of driving a manual. But I also bought mine when someone installed a heavier clutch kit so it helps a lot. i
I've tried looking for a fuse and haven't had any luck yet. As far as I know, it's probably something you can bring to the dealer and let them hook their software up and get into the ECU to turn if off.
Unless someone else can give us an easier answer