Darwin Boblet

A stranger met in a parking lot told me that her husband converted her outback from 4wd to 2wd by doing something (unmentioned) in the fuse box. Seems a bit dodgey to me but SHE claimed it gave her about 30mpg afterwards. I have a Forester all wheel drive and was wondering if it would work on my car... or even if it were possible for that matter. Anyone know??