gsrxx420xx

hey everybody, i am new here and i am thinking about gettin the new 900 nav unit. I tried doin some research but couldnt find to much info. I kno i need a dash kit, but i am unsure which one. A metra one, or should i look for the oem one? I know i will need a pac swi for the steering controls. What else do i need? anyother types of harnesses or wiring? any tips will be greatly appreciated.... thanks rich