For those wanting 4 volt preouts and Appradio functionality I would recommend you look at the Pioneer AVH-X8500BHS. while It does lack the capacitive touch screen appradio models have, it is a better (IMO) all around unit.
AVH-X8500BHS - 2-DIN Multimedia DVD Receiver with 7” WVGA Touchscreen Display, MIXTRAX, Bluetooth®, HD Radio™ Tuner, SiriusXM Ready, and AppRadio Mode for iPhone® and Select Android™ Devices | Pioneer Electronics USA
It can be found on Amazon for around $450.00
Here is a picture of my X5500BHS installed (The X8500BHS looks identical)
