I am familiar with the term "pot metal". You never know what's in it as far as chemistry consistency is concerned. It would seem very strange to me that a company like Losi who produces a world class race roller buggy and competes at the highest racing levels in the rc world, would make a critical component out of an unpredicitable metal, and compromise their quality. I am not trying to agrue with you, it just sounds strange to me. However, I have seen stranger things before.
I also understand that a chain is only as strong as its weakest link. 7075 although a much stronger alloy, could cause more damage if it transfers to the chassis.
Thanks for all the input.