Today I spent some money on a set of rims:

They are powder coated flat black
205/55/16 tires
16inch Wrx 6.5inch wide 55 offset rims
when installing on the front they do rub agianst the caliper protector that is the problem.
I need to space the rims out 1/4inch so that it clears the aluminum protector.
Here is my question:
I replaced my rotors when I bought the car. I kept the old ones just in case.
I am thinking of getting some rim spacers between the rim and the rotor, out of the spare rotors I have. My brother is a machinist and he can separate the bolt pattern face off of the rotor to give an end result of a spacer. It will be iron. Is there any problems I may encounter??? at all??
I've seen some spacers that are made out of aluminum...... Is there any advantages to aluminum that iron can not obtain.
For summer, I will have these new rims on and replacing all struts and shocks.
I am thinking of getting KYB GR-2. Any thoughts?
I am not planning but it's an option.... What is that protector? and can I cut or shave it or bend it in?