I am not sure, but I think the hinge pins of my other cars have got bent less in the past. It could be easily be solved, either by using better steel, or they just use some spring steel, which is more flexible. I will cut some spring steel into pieces to get that solved. I dont't think that due to better steel the arms will break...

I remember that someone advised to use hinge pins of a brand I can't remember, as they have better steel.
An other improvement would be to use inserts made of rubber, instead of plastic.
My LRP/ZCar Pro Truggy had rubber-inserts, which have lasted for ages.

@WonTonsChicken: you should be fine with filling the diff as advised in the manual. I have heard that the Silicone Oil expands when it gets hot, so you have to leave a "gap". Others say to fill it up completely, but I never did that (just almost full).