there's no reason to cut into the dash. At worst they'll drill a small hole somewhere out of sight for the cable to come through but there's plenty of places to route cable so I probably would doubt that they'll do any drilling/cutting.

 

I control the ipod directly from my deck. I don't ever have to touch the ipod. If yours is the same way, I just ran the wire from the back of the deck to the glove box. You can just tuck the wire underneath the dash that leads to the glove box. You could never tell there is a wire. I never have to carry cds again.