I first went from the stock crap unit to a Pioneer Avic-D3 and now I'm running a Kenwood DNX 6980. Both massively improved the sound, the Kenwood even moreso. I would just go aftermarket double-din touchscreen, it looks very clean and OEM+ overall, I think you can pick up the Kenwood for $700 or so on Amazon, but if you find a nice aftermarket unit without navi it will be much less.