wtf is wrong with you people? maybe next time u should give a proper title?

#1 check is pidgin has a notifications and if not try to port them and intigrate into hildon notifications ( but it would be painfull to get them all the time.

#2 just connect car set with bluetooth as headphones and it wouldn't matter what sound you transmit from n900 (music/radio/calls/whatever_makes_sound_on_n900)

all modern even cheap audios in car have bluetooth nowdays, even toilets have bluetooth now =)

http://www.youtube.com/watch?v=61a0qHFcQE4