Decent handling susp setup?
Surprized more folks aren't looking into other alternatives besides mustang wheels. Don't the crown Vic cop car wheels have the same bolt pattern in 16"? How about the early Toyota pre-runner (the blue ones with body kit) wheels. They're 5 on 4.5" too and look pretty good. Some of the newer jeep wheels look ok too.
The center register size in the front is easy to fix by having your machinist cut the hub snout down to fit the wheel.