I can answer that. Windows down -forget it. Wind noise on the mic, at least where I've mounted it.
Stereo on, it can recognize voice commands. Stereo blasting, nope.
But I don't think that's so bad. I can't hear my passengers when the stereo's blasting. It doesn't seem like I ought to expect the computer to, either.
It would be great if there was some way to filter or process the sound to listen only to the range of your voice and then to try and filter out extraneous noises like car rumble or wind noise. I know how to do it in a post-processing environment but haven't ever heard of it being done in real time for voice.
I'll record some audio from my Logitech install while on the road and post it so you can hear the noise.