I think I even read somewhere that if you get mazdaspeed accessories some of them are actuall covered by Mazda if installed properly. Something like 1 year on the intake if I wasn't dreaming and actually read it somewhere.
I was reading the booklet that the dealer gave me on warrenty last night and it is vauge as hell. It has a lot of 'what is not covered' which includes non-Mazda replacement parts. It also includes under 'factors beyond the manufacturer's control' which includes racing, accidents, alterations, modifications, tampering etc.
Nowhere does it say warrenty void in the entire warrenty booklet. I am not a lawyer but my understanding is that anything you do or put in your car is not covered my Mazda under the warrenty, but not voiding your entire warrenty either.
Aftermarket companies are protected by Magnuson-Moss Warranty Act of 1975 which through my understanding states you don't have to use Mazda parts or Mazda services when having work done to your car. Once again I am not a lawyer or a mechanic so if anyone wants to clarify I would be very interested in learning more about warrenty and our rights as consumers.