I have several different models of CDM mics that I have tested with the same radio taking note of audio quality and gain. While doing this, I have noted that the RMN 4026B DTMF mic worked the best, and the HMN4069E came up second. interesting that the RMN4038 was the worst, and thats the one Moto says is supposed to be for the radio. I want to get some more 4069's but wonder what the revision changes are? I have searched for a while including here with not many results. Within the same model number, will other revisions perform the same as my "E" version? And im guessing that in true moto fashion, those revision changes would not apply to other mics?