Aluminum screws into aluminum threads
Bad idea. If you can manage to keep the anodizing from stripping off the threads from wear, you will have limited sucess. I would (not use those heavy diff housings...) use stainless screws if you are trying to pump up the pimp factor... Aluminum screws into an aluminum part, if it's raw aluminum for both, after some time (sometimes not much) the aluminum will weld itself together. If I were you and you were really hooked on the blue aluminum cases with the blue screws, either use anti-seize on the threads, or invest in the 'anodize' paint from one of the major paint manufacturers, i think it's duplicolor and available at auto parts stores, and paint your steel screw heads.
Speed Merchant Rev7, Tekin, TQ Racing (wire), Team Tamale
RC Excitement - Buy where you race, support your local tracks.