Their is a wired aux in jack in the Nolan audio kit for the helmets. A jack to plug in things like Ipods or other sources. That is a stereo source. The Bluetooth connection supplied by the N-Com module is not stereo.
For things like phone calls or hearing the nav instructions this is a distinction without a difference. Just no big deal. For using the 2820's multimedia player functions, however, it would be a real issue.
Two options would be to use a patch cord from audio out on the 2820 to either the aux in jack on the radio or the aux in wired connection on the helmet. The latter loses the completely wireless connections of the helmet. Neither option is as nice as it would be if the helmet's Bluetooth capability were that of a stereo headset. But at least there are options.
I can hear the bike's audio just fine with the full helmet on. Have in fact gotten used to it that way. So if I wanted the 2820's MP3 player would probably plug to the bike rather than the lid. Quite frankly with the XM and a good MP3 disc in the radio I doubt I'll do either though.
Even with the deficiency of the N-Com unit not being a stereo Bluetooth connection it has worked great as a phone tool for over a year now. Tieing it all together with the 2820 adds so much functionality, increases ease of use tremendously, and is just pretty cool on top of all that. So I'm pleased so far.
I actually liked the mapping display of the 2620 better then the new 2820. There were also a few functions and controls offered within the 2620 that the 2820 just doesn't do. If it were only a nav unit to nav unit comparison quite frankly I'd choose the 2610/2620 over the 2820; though some of that initial reaction is of course based on just a greater familiarity with the prior unit.
Navigation is still good with the new unit though. And it seems every bit as "intuitive" as the old one displaying things you'd actually want to see when and just prior to your actually needing to see them (even if you don't know yet that you will). So the differences between the two aren't a knock on the new unit's capability. Just that it's functions and controls have kind of dumbed down a tiny bit. If you're going to take advantage of the Bluetooth ability, however, its addition is a utility that more then compensates for the other minor losses.