It's only oem audio features that you'll 'lose'! once you remove the head unit(s) in the dash, the DSP amplifier and oem speakers that's it, you just have 'no' audio. It's not as though you lose AC controls etc. Depending on which double DIN you fit, is whatever features you'll gain, i.e bluetooth or GPS etc.
Keep in mind that if your oem head unit setup has things like speed dependent volume or phone prep which routed audio through front speakers, then features like those would go.
JimLev and a few other members are probably more knowledgable about oem setups than I am, I focus on high quality aftermarket setups and equipment.
Last edited by DennisCooper!; 01-23-2013 at 11:56 PM.