My friend broke 2 ofna motor mount screw the first day out, they suck. RCscrewz kits are stainless screw which are fairly weak. Racers edge IDK about them. Tony's Screws are top quality from what I hear. Locally, we have a deal with Fastenal and we get 12.9 grade screws which are very strong. It sounds to me like you just need some good strong 12.9 grade screws. I tighten in a criss cross patern and never use threadlock, and I don't have issues.