Welcome
Well to help better direct you, we really need to know what direction you want to go with the car, ie planned mods & stuff you want to change as well as what you want in a stereo & nav what nots. As far as the Bose stereo, I personally feel it's nice on my touring/sport, but there are plenty that will write it off as junk. Maybe it doesn't shake the ground, but it sounds nice to my old ears. Navigation is another area where you can get better units after market, but what do you want it to look like. I skipped nav on mine, because : 1 when I drive it I know where I'm going, & 2: my cell phone does a great job of navigation with 2 way voice directions via Google. (I speak & it speaks turn by turn).
You can save money initially on a base, or you can end up paying a good bit more to get it where you want it. I would suggest reading a lot of the postings in the audio/ video forum & get an idea on what you want the cabin to look like inside & go from there.
Good luck with your decisions.