The Foz rims stick out 5mm further than Impreza rims therefore giving you an extra 5 mm from the stem but the perch could be a problem, I had GT Foz rims on the blue WRX offroader with 205/60-16's and there was still a bit of room from memory......they never rubbed anywhere so use the tyre chart to compare, I think WRX is 53 offset and Foz is 48.

Tom.