Does it really make a difference buying the original parts?
I have been told that I have to use BMW brake pads or I will have noise. True?
on 2004 BMW 325i
yes the newer model like yours it will make noises if rotors and pads are not OEM but 80's model its okay i installed some of those autozone brake pads.
Why would this matter? Just wondering. I have used other routers but not pads.
Different 'blends' of materials used for different types of application/performance levels-to put it extremely simple. If rotors were engineered for use with ceramic pads and semi-metallic or organic pads are used you will likely have a difference in stopping performance and pad/rotor life , and problems with rotors warping etc.