i have heard of this setup only problem is its sounds pretty terrible, bluetooth streaming is already compressed and hollow sounding and fm modulators make sound even bad so although the poster would be able to achieve what he needs i don't think it would be worth it in terms of sound quality, i listen to purchased music at 256kbps so this would sound pretty hollow but if predominantly mp3 songs downloaded from th internet are to be used then its a good device,
but why can't the poster simply make playlists or use a software like genius or iTunes match etc or a number of apps on other platforms to get the music he wants without having to skip, or he could place the phone somewhere where he can press the voice command button on his phone without taking his eyes off the road and press the voice button and select or skips songs, that isn't dangerous it would be just like changing gear in a manual car