I am a pilot and own several pairs of DC headsets.
This is something I am wanting to do as well for comfort reasons and for contesting.
Icom mic's are 600 ohm... DC mics are 150 ohm.
Now that the WX is cold, I'll start to play with this idea. I am not sure how the Imp difference might effect the audio. I wish to make the addition of the DC's as streamlined as possible and not get into any sort of mod's to the headsets, since I use them for flying as well.
They are great for CW listening.
The DC headsets are NOT cheap... they run between 250 and 400 bucks. Some of the cheaper versions are just as good and half the price. Look on www.landings.com
for places to purchase them.
Drop me an e mail and I can keep you posted on any progress on email@example.com