I love the pearl, one classy ride! Anyway, welcome to NPORA!
In reference to improving your pathy, you've come to the right place to blow money. For the stereo question- I have the Kenwood DBX500BT, which fit into the stock location with no trimming, does bluetooth, pandora, CD, Ipod, aux, whatever, and is adapted to the factory Bose speakers. Their sound quality has improved a bit, and overall I'm very happy with them. However, if you have the $$ you might as well upgrade your speakers, if that is in your ultimate plan.
Here it is
What are your ideas for the pathfinder? Trail riding?