Thanks guys for the replies. Yes, currently we are using chinees E6 and for communication they work fine. Using ear plugs does silence everything (headset, wind, engine, ...). Now we crank up the communication units volume to max. This makes sound VERY clear even when cruising on highway. Problem is, I can't hear both phone and communicator at the same time. So have to keep my eyes on the damn cell phone screen to follow navigation directions! I was thinking getting a 30k could be a good upgrade so can hear both communication and navigation directions at the same time. But need to make sure still can hear everything clearly with earplugs!