I have an 04 EXT that has navigation rear dvd and bose. I would like to replace my stock navigation with a Pioneer avic-z2 that i currently have in another vehicle but i have a couple of questions about the stock navigation. First where is the GPS antenna located in the stock navigation? Is it inside the unit itself or located somewhere in the vehicle? If its not integrated into the stock navi does anyone know if it will fit or can be adapted to a pioneer navigation so that i dont have to install the antenna that came with the pioneer unit? Can anyone tell me which adapters i will need to buy in order to keep all stock functions working in my vehicle using an aftermarket navigation such as steering wheel controls, bose system xm ect. Finally will any features be lost by adding an after market navigation (are there some things they just do not make adapters for) After installing the aftermarket navigation i would like to sell the stock navigation can anyone tell me what models my stock navigation is compatible with like other escalades or possibly hummers or chevy vehicles?