Knut, The K3S as originally shipped does not have a design flaw. Like virtually all 12-V-class transceivers using currently available MOSFETs, it was already right around -30 dBc or better, worst-case, for 3rd-order IMD. We simply found a way to make it better by a few dB, and we're offering to make this upgrade at no charge. 73, Wayne N6KR