On a somewhat similar note, does anybody know of a way to adjust the volume of the navigation voice? My issue is I'm going down the road listening to Pandora at a normal level while navigating at the same time. Everything sounds great in Pandora (playing through Sync via bluetooth), but when the navigation voice kicks in, I can barely hear it. It's like the nav voice and the Pandora output levels are way out of sync. So I'm looking for a way to increase the nav voice specifically.
Oh, and +1 for market apps to add/replace the stock voices. The ICS stock voice isn't bad, but options would be great.