I just put a set of Enkei Fujin wheels on my BRZ 17x7.5 40mm offset. I wanted to set my scrub back to factory so I am using a program from racing aspirations to determine the scrub radius of the BRZ. These are my results.
Factory scrub radius with 48mm offset +20mm or .75 of an inch positive scrub.
With 40mm wheels +28mm or 1.10 inch.
With 225/45/17 1/2 inch taller tire +26mm or 1.00 inch.
http://www.racingaspirations.com/mods/tg7n7uwl