Since the iOs 4.1 upgrade on my 3GS, the sound is not clean anymore in my Prius. We can now hear small scratches during the songs. I have tried with the 3GS of a friend same problem. I don't have the GPS version of the Prius, only the JBL with iPod/iPhone USB kit. I guess the US equivalent is the Prius IV. Does anybody experience the same issue?