I am thinking about doing the double DIN conversion to my 03 coupe. I want to put the Pioneer AVH-P4000DVD (http://www.crutchfield.com/App/Produ...tab=review#tab) in there. My question is this:

Will my beloved steering wheel buttons be compatible with an aftermarket unit like this?

 

And another question, I have the stock navigation system in my g, does the Double DIN kit that most people get even work with the nav systems?

 

You need the PAC SWI-PS for the Pioneer.

You can use the JDM DD kit, but you may lose the navigation voice without some modification. Search and you will find some recent threads about the navi voice.