I had the same issue as you for many many years.
I long to be able to plug my iphone with USB into the car, and have it charge and sync my music.
I found an amazing product, which I have not tried out yet.
I will tell you the info, all I request is you tell me how it works and show me some photos if you decide to install it!
check them out at:
I haggled with the guy and got him down to $500 if I send him a wire transfer, I believe the product is $700, but you need to also get it installed
Check it out and let me know what you think