question about stock radio's

I was wondering if there is a difference between the wiring for the stock radio in a 2005 prius and any of the radio's for the 2007/2008 model prius. I have an '05 prius and found a few 07 and 08 radios with xm radio and aux inputs online for tremendously cheaper then from dealership (dealerships around me want an astronomical $1300-1500 for a stock radio). I found some cheater ways to put an ipod and xm radio into my prius, but I really would like to have them work through the mfd and stock radio. so this is the best option I have found if it works.