i've bagged on the K70x/M3 combo before with the brighter AD8065 opamps and Alps Blue pot. i think the AD843 sound excellent and add a little extra warmth and are cheap. i also think a CP2511 TKD pot is a worthwhile upgrade for a difference of $60.
i would also encourage you to post specific queries re: M3 over at the amb forum as well.
i would also encourage you to post specific queries re: M3 over at the amb forum as well.
