I'm planning on getting an aftermarket DVD double-din unit, probably the Alpine W200 or something like that. I know I need to get the double-din trim piece, but i'm confused as to why i would need the ac controller unit as well? Why couldn't i use the one that's currently in my car (2005 G35 coupe)?

Why would i need to spend an extra $270 for this unit? Can someone help me out and explain?

Also, am i missing anything else? any other pieces i need? I checked grubbs' website, and it says i also need the double-din bracket in addition to those pieces mentioned.

 

I see that you are fairly new. You are going to get flamed if you don't search. There is a TON of info on this. You can't use the stock controller because it is part of the Bose/factory radio circuit board. You would have to hack up the circuit board to get it loose. You NEED it, end of story. As for everything else...search...there are multiple threads that have pictures and lists of what you need.