I've been actually looking at space savers in the past month for the car, so far it looks like its about 400-450 delivered to Perth for one. I have yet to even bother call up the local dealer based on the price differences last time I called on Injectors + associated bits.
My reason for an actual spare is we go out to the 'outback' a bit, no phone reception so a spare tyre would be much needed incase of a situation.
'09 BMW 135i, Lemans Blue
'97 Nissan Skyline R33 Series II GTR V-Spec + mods
'97 Nissan Stagea RS4
CRG Road Rebel 125