I have r40 on all my cars. Yes, rust can develop. Cro-moly rusts. Your stock lugs rust too. I do not use the lock version. I don't find a need, wheel locks are easy to take off in seconds. I have used impact on mine, but usually only for taking them off with a 17mm socket. If cost is a factor, kics are not cheap like mcgard. The threads do not go end to end. The engagement area is about the same as a stock lug.