I went the other way when grafting alloy S4 Rx-7 Hubs onto the toyota stub. I had the alloy hub machined out (by a bees dick only) and a steel sleeve pressed into the hub to allow the appropriate sized wheel bearings to fit.
Obviously the Toyota wheel bearings did fit the Toyota stub fine, but the bearing OD's were not quite right for the mazda hub, thus the requirement to sleeve the hub to get it all right.
Also note this in my racer which is reasonably light, and not driven on the street, although it does cop a hard time through corners, kerb hopping and braking. I've had no issues at all and it provides less unsprung weight (and the Rx7 S4 disks and calipers also help out)