In the 07 ,the connection is throught RCA cables, the 08-09 throught i-pod interface,.....Is the SIGNAL the same Quality ???

 

I'm assuming the RCA cables are connected to the ipod's headphone jack? Whereas, the ipod interface in the 08-09 is connected to the line out (direct data feed). The headphone jack is amplified and eq'ed, which is less desirable when connecting to another amplified stereo system. The settings might conflict with one another, and it will be a slightly noisier, more distorted signal.

Better off using the line out (ipod interface in the 08-09).

 

Thanks ,but I have 07 g35s sedan ??

 

Well I guess you don't really have a choice then. From what I understand you can get something like this
SendStation - Products - PocketDock Line Out USB
which will give you the same signal quality because you'll be going through line out instead of the headphone jack. But you still won't be able to control the ipod through the car stereo controls.

If you just go through the headphone jack to the RCA cables, it's not a total loss or anything. You'll still have a good signal, just not quite as good as the other method. You might want to disable the EQ in the ipod settings and just use the car stereo to adjust audio settings.