Motorola Droid with 2.1 OTA Update installed manually. Speech-to-text seems to work pretty good under ideal conditions. However I cannot get it to work in my car - it produces garbled text, if it works at all.

In all cases I have muted the stereo, and it is just me in the vehicle with what I would consider minimal road/wind noise. I've tried speaking clearly and loudly with no better results.

Two Questions:
1. Is this inability to filter out background "white" noise to be expected?

2. If I had a Bluetooth headset, would the speech-to-text know to use the audio from the headset vs phone microphone? If so, any real-life data as to whether this works reliably in car environment?