Stainless is a bad alloy for rc fasteners. If you have ever tried to drill, tap,thread, or cut stainless it is harder to cut than carbon steel, but for some reason or the other it is to soft for the tools we use to wrench on our cars with. I once had all ss fasteners on my 1/8 buggy and ended up stripping them all out. It wasnt from bad tools either, i use the mip's which I feel are the best but the screw would strip from trying to break loose. Stick with 12.9 alloy steel.