They look a bit "Japanese" but i like them and i think they will look great on your car, i like the idea of using non-standard Mustang wheels to seperate yourself from the crowd, you already lowered so it should look really bad ass.
The one thing that jumps into my mind is the offset and back spacing, the Stang is wider than the Z so you need to make sure it will clear the brakes and steering componenets.