I have a set of 225/45R16 Hankook RS2s you can have for cheap. nothing wrong with them,except that they're not 255s.
225 fits with no issues under Imprezas on RS wheels,so they shouldn't be a big deal on the Legacy either. They're a tad short, but that just makes your speedo read a touch high and shortens your gearing slightly. They are also stock L diameter, if you ever wanted to toss them on the green wagon or whatever.