Yep, a B body axle in an A body is one trick for sure. Buy custom axles with the center register turned down to the correct size and then the Mustang rims bolt right on.

Up front on an A body car the 73+ spindles make the track wide enough that you might not even need a spacer. With factory 11.75 rotor the hub on the rotor needs to be turned down a hair and then the Mustang rim will slide right on.

This car uses aluminum hubs to reduce the weight but they are the same width as stock hubs so there isn't anything trick going on. Just weight reduction. The rotors are factory Viper rotors that have been re-drilled for 5x4.50 pattern and then 17x9 Mustang rims slide right on there with 275/40-17 tires.