As stated.... Diff protector... Bought it 5yrs ago never put it on.... $50... If it isnt sold in a week or two it goes on ebay... there is one on there used for $75 plus $20 shipping...
For which diff? I know there are different fitting diff skid plates out there, and some don't fit the same between the R160 and the 180.
TBH couldnt tell you... being that it was supposed to be for a WRX my guess would be 160... nothing a drill cant fix