I have an OEM trailer hitch for sale for a 2009-2013 Forester. It replaces the rear bumper beam. Here is a tutorial on how to install it http://www.subaruforester.org/vbull...ru-trailer-hitch-install-2009-forester-60320/ It only needs the hitch insert with ball ($20) and the wiring harness (Curt has them for $30). Subaru price is over $300. I'm asking $75. It is used. I ground/sanded/removed the rust and coated it in undercoating. The last picture is what is exposed after installation. That's on my wife's car. It's due for some TCL. I like how this turned out. The OEM hitch is so much nicer than aftermarket as it's more hidden and doesn't hang below the bumper.
Bump. If this doesn't sell, I might be tempted to swap the wife's hitch mount out for this one and do it again.
It doesn't matter what you put on it. Any physical contact will wear down any surface coat. Undercoating is quick, easy and cheap. All the rust was removed with grinder wheel, die grinder and blaster. It was then coated. You wear any coating down (including the factory powder coat) and you'll need to re-coat it. Undercoating will keep the surface free from rust. If you tow a lot, the slot and chain ring holes will eventually need attention no matter what. This is 1/3 the cost and looks just as good as new.
And it looks like it would be super easy to hit it with the wire wheel with all of those flat surfaces! The inside of the receiver looks like it would be the toughest part.
I had to use an extended cone die grinder to clean that up. I used primer/enamel inside the square tube just so I wouldn't add thickness like on the outside.