You would probably want the ground loop isolator mentioned earlier in the thread to eliminate engine noise from the AUX input.

Can't figure out why that input wasn't properly grounded/isolated from the factory since these are luxury cars. Same with the placement of the power adapter in the center console box, should've been mounted about an inch lower so any type of lighter adapter can be used with the console shut. Sorry about the brief whining there been playing around in the center console yesterday and it was a little frustrating - tons of room in there tho.

 

I have found that the engine noise is only present when you are charging and playing at the same time. When I pulled the charger out the audio became much better...

 

Ditto. No engine noise. I'm just using the basic radio shack cable - $6.00.
What is the VAIS you guys speak of? Ok..ok...I'll search.

 

True but it shouldn't have that issue at all - I prefer to charge/play my iPod at the same time and if you hook a satellite radio through the AUX you'll definitely have the engine noise issue.

 

Can someone that has used the sik adapter comfirm that a noise isolator is needed to reduce the noise from the aux port?

 

Yes, I was one the one who orginally used the SIK adapter and you do need the ground loop isolator. Without it you'll get the high pitched whining sound. I have since gone to a direct connection (using the DICE unit) which works and sounds great - bought it for 200 and paid another 75 for installation. But I understand not everyone may want to go that route.