I am looking for the same. mine have started buzzing in the bass like that since summer and are not getting better. I have the NAV radio and wheel controls I really dont want to give up as long as they work. I called Crutchfield too and they told me I have an amp on each speaker and they are not compatable with aftermarket speakers, That I should replace all 4 speakers and drive them with a four channel amp (Alpine $149.99)
http://www.crutchfield.com/p_500MRPF300 ... l?tp=35782then I found this page that sort of says to buy infinity of JBL because they are 2ohlm and that if I had the amp you can extend the wire and power your new speaker with it.
http://www.crutchfield.com/learn/2002-2 ... ryspeakersI wonder if anyone has done that and how well did it work? it seems that way would save me $$ on the amp since there is enough power now. Also would save me a lot of wireing work that I don't care to do now that I am not an early 20 something anymore.