front bumper did the trick for me on my Schumacher aero 4wd for indoor racing. i have driving the B-max4 iii for in 2015 and did try the hard arms , i did not break a lot off arms, but can say that on hing grip astro or carpet , the hard arms are quicker to brake, the snap sound proves it
i bought 2 used cars last year and both had bend hinge pins and pieces broken out of the arms . the RPM arms are indeed a good solution, but remember, the guaranty wil be lost when you start to grind stuff away...