Three of us in Oz bought a secondhand set of SRT8 rims and tyres (VGC) and split them between us. The logic being that the Fix a Flat is ok in the city for a normal puncture and you also have phone contact etc. However if you are out bush and get a blow out the FAF is not going to work and you can be in an area with no phone coverage, so you are pretty well stuffed. Consequently when travelling in remote areas I carry the spare in the boot. Keep in mind when you put it in it takes up a fair amount of boot space. The other issue for us is the availability of a tyre to suit if you get stuck outside a major town or city. If you do a lot of remote travelling I would strongly suggest getting a spare. At least you are not going to have to pay for a tow truck or leave your car on the side of the road until you can get help. As another forum member suggested they are occasionally advertised for sale on the forums, so its worthwhile keeping an eye out.