I know a few people on this board have noticed a "feathering" problem, my question is to the people who replaced their coilovers with any other brand (Tein, HKS, S-Tune, ect), and have over 3k miles, have you felt any problems (feathering) in your Z? I was reading somewhere that the feathering problem could be the result of the coils/shocks/struts instead of alignment/tires ect.