PLEASE help me decide. Local installer says he can do either of the above in my 05 430. he thinks the sirius option will give better sound quality & programming. ilive in nyc area 7 have had xm for a few years in office & other cars wiyh good results but am willing to try wharever works the best. also, it is not important to me if contorl is through the ml hu or only from the alpine or commande piece. all suggestions welcome.