options for upgrading to aftermarket stereo from factory bose + oem nav

forevamackin

hey all,

i've searched and can't seem to find any info on how to go about upgrading my factory bose system with oem nav. i plan on replacing everything speakers,amp, and sub but i need to know what my options are.

option 1: replace oem nav with aftermarket double din w/ nav

is this possible? what do i need to do this? what functions would i lose if i went this route. also this would leave me with a non functioning radio underneath. correct?

option 2: replace factory radio with single din or double din
crutchfield won't let me view double din units after selecting my vehicle so im guessing having two screens isn't possible? can someone verify this? if i went either single or double would my factory navi still function normally? what functions would i lose? steering wheel controls, bluetooth voice ect?