According to Tirerack, the et52 of the WRX wheel will fit the 2012 Sport with a et48. In looking at the difference, referring to a wheel offset comparison, here's what I came up with:
The clearance from stut housing to the inside of the wheel will be 4mm LESS
The outside edge of the wheel will RETRACT in towards the body by 4mm
4mm is a little more than 1/8 inch. I can't imagine that Tirerack would sell wheels with such an offset if they didn't fit. I've used them alot over the years and had no issues with fit up.