They will stick out 20.7mm further than the rims I have on an identical car.
Mine has adjustable rear arms shortened by 15mm.
Mine has rear negative camber.
Mine still trash the tyre sidewall.

Rear fenders on MY05-07 STi cannot be easily modified, they do not have the same return under the fender that a WRX has hence nothing to 'roll' They have a sharp edge that's spot welded with the flare stuck over the top.

Unless you fit Outback style suspension your car or stretch on a tyre 50mm too narrow for the rim it will be no good with those rim specs.