Weird because the bushings in the conrod are also brass....
Yes, with aluminium rods I have seens corrosion spots. It is not that strange because nitro is oxigen and oxigen is needed to start corrosion. With the acid produced by burned nitro it can eat into the surface of metals. That is why a good fuel with castor oil or an afterrun treatment is needed to protect the engine.
Speed is only fiction but a 130+km/h MRS4 is for real.