Okay. IIR my directions C:

Your car wants a +50mm wheel. This means that the bolt plane for the wheel needs to be 50mm to the outside of the center of the wheel. The wheel you want has the bolt plane 35mm to the outside from the center of the wheel. In order to get it to line up with what the WRX wants, you have to get the bolt plane to be another 15mm further to the outside, which means you'd have to grind material off of the wheel, which means it ain't gonna happen.

If you had a wheel that was at +60mm, then you could buy a 10mm spacer to get it back to +50mm and you'd be good.

Tirerack has some info about offset. Maybe their picture will help explain it better.

And don't forget about bolt patterns.