i have a pioneer 6400 7in. in dash flip out screen that i wanna install in my gsr. i have seen cars with it but it doesnt flip out correctly because of the AC controls. in other words how can i put this in so it flips out all the way with being stopped by the dash ?

 

Unless you mount the HU "extended" out of the dash or your Pioneer HU has an "extendable" screen, then it can be a real problem, some units work OK if installed in the bottom instead of the top of the "double din" opening, [a little modification the the mounting kit is required].
The other thing that you can do is mount the HU where the center vents are, [more custom work] but it is a good spot, gets the screen up higher, this can be done without damage to the dash or vents, some modifications will have to be made to the duct work, depending on depth of HU and how far back you want the HU to sit. This is not an easy job, and unless you are comfortable doing fabrication, I suggest you do not try it, leave it to a pro. 94