i have the volcano epx pro(brushless) and i also broke a stock plastic part. i thought about going alum, but dont think its worth the cash.
instead, i bought a set of traxxas e-maxx skid plates. i drilled out holes to match the screw pattern on the underside of the volcano.
see, the stock bumpers are a joke! they dont have enought give and the they dont stick out far enough. the emaxx skid plates make nice long flexable bumpers. this will help save the a-arms and wheel hubs.

i did the same thing on my exceed buggy(also brushless and shares alot of parts with the volcano) and i have jumped it at full speed 8-10 feet in the air without breaking anything!