Suspension difference between stock and springs + struts + bushings + tires is HUGE.
Don't forget that these things came with 205/55 RE92 all seasons stock. Just tires is enormous. Back in the day, people worried about dealers denying warranty issues just because they had new wheels and summer Z / W / Y rated tires.
Now WRXs come with 17x8 and summer W rated tires... oh how the times have changed.