rims for 06 mustang

A little more information would be helpful. Factory wheels or aftermarket? What size and offset? Most likely they will have the wrong offset and be tucked into the wheel wells pretty far. What are you using them for?
 
I think the bolt pattern will be fine but the offset is likely to be off, the wheels will probably be tucked into the wheel wells pretty far. You would probably want a 35mm to 41mm offset for your car. Are they local pickup or shipped, if they are local then maybe see if you can test fit them.