Plastic bumpers are pretty common on cars nowadays and they aren't exactly as weak as some may think, and I don't think I've seen a BMW that had anymore plastic then that on the outside so this could just simply be the certain model problem also what's wrong with the door handles being made out of plastic? It will hold as long as the car will run that's for sure unless you'll really try to break them. Most of plastic components under the hood don't really require to be metal, and they last long enough, a lot of them probably never(as long as you keep your car) even break if handled properly and I'm pretty sure they aren't as hard or expensive to replace as their metal counterparts would be. Pretty much all vital components and the body itself is still made out of metal.
Nigga have you ever popped open the hood of a bimmer? In 5 years, those plastic parts under the hood get extremely brittle and crack since their compacted together right next toward heat sources like exhaust headers and radiator hoses. BMW makes it so you can't work under the hood, they want you to take it to a dealership and pay their over-inflated prices. I've done work on late 2000's BMW models and you gotta go through a whole bunch of BS to do simple fixes, like BMW doesn't use belt driven waterpumps, they use a plastic electronic pump that's $600+ just for the part, and the amount of shit you gotta go through to change it will bring up the labor costs will over $1000. With a normal, mechanical driven water-pump you just gotta take off the belt, fan blades, undo like 5 bolts, replace the waterpump and gasket and repeat the process. For most late model bimmers they stash the waterpump under the engine block above all the wheel bearings/tie rods/hoses that you gotta wiggle through and sometimes take off. Dey be expensive, so you better be elliot rodgers or have the dough to afford one.
