If you want to be able to control it from the touchscreen then yes you'd have to get a pioneer dvd changer. I think sportsfan21 found a nonpioneer single dvd that worked. I'm not sure you'd have to pm him. If you don't care about being able to control it through the touchscreen, then you just need one that has an rca a/v output.
I never did find out if it works for sure because no one here has bought it yet. I think it'll work, but I no longer needed the changer so I stopped looking into it.