Upgrade from RCD 300

[viperpsych]

Sorry guys i have done a search.

As you can see from my postcount i need some advice.

I have a 56 plate 2.0tdi 140 estate.

Im looking to get a screen into my car.

Im not bothered about sat nav as i have a Garmin.

I just want a better stereo that can play music and video.

Ideally i would like to connect my iphone to it and play stuff from there.

I have seen the rns 510 which i presume you can load stuff onto the sd card and play from there. I can do that.

Is it just a case of plug and play for the rns or would i need loads of extra cables.

Or would i be better off with something like a pioneer appradio?

Any comments greatly appreciated.

Thanks

Dan