whatever material you have on the car it will always eventually break sadly, in the event of a crash of course.
i got few nice alloy parts on a hyper 7 few years ago and found it out.
but if you add something thats alloy it will break the surrounding plastic parts, because the plastics are designed to flex to avoid breaking, but if there is a big piece of alloy bolted on it will stiffen it all up making it easier to snap the plastic.
i would invest in some spare parts instead
