Personally, I would upgrade the H/U first, but that is because I just cant stand stock radios. But I have never bought a car with a stock nav or anything like that. I always get the most basic system and upgrade from there with what I want. I upgrade mainly for iphone integration and ease of tuning. But you can always get a fairly cheap LOC and get the speakers in for now and upgrade it later. But my Camry's stock system ******, and it got a lot better just by upgrading my H/U and doing some time and phase alignment and just tweaking it.