From what i know since i want this unit too, appradio2 extensions (lastest version is beta)will make both headunit and phone unstable. but since we don't have controls in steeringwheel it'll be nice to have siri do things for you like dial out (oem voice commands does not have a good voice recognition)
PrimeMotoring has a one piece fitting kit and metra has a 2 piece (left+righ).
I'm waiting until the entire cover with a 180mm space is available.