Swapping single CD for 6CD in 2006 Xterra S

I wanted to know if it was possible to swap the single factory CD for the 6 CD in a 2006 Xterra S. I couldn't justify the $4000+ extra to buy an SE, just for the head unit. The reason for the swap is that I want to use the factory iPod integration unit. I really don't want to have to use an aftermarket radio to get what I want. Any help would be greatly appreciated.

Thanks!