Marlin Stereo Upgrade

I'm finally getting around to updating my stereo on my '99 Marlin. I'd prefer to keep everything under $1k, especially since there will be added installation costs, and I'll probably wait until a good sale since my season is almost over and I'd like to get this done before Spring launch. Currently I have stock Kenwood receiver in cabin with remote at helm, 2 small infinity speakers (I think 4") by the anchor locker, and 2 larger West Marine speakers (I think 6 or 6.5") on each side at the helm. The entire system sounds kind of crappy and the port helm speaker wire needs to be re-run. At the lower end option I'm considering just replacing the kenwood with something like a fusion RA-205 and upgrading the helm speakers. At the other end I may be willing to spend more on an amp-based system and/or maybe add 2 more speakers underneath the walk around steps on each side where there are currently 2 small inspection ports (not where the cockpit lights are but lower down) and maybe even a sub underneath the port bench seat although I don't want to lose that storage area where I keep extra fluids and supplies. Most of my listening would be through my oversized iPhone, but I generally like hard wire connections over bluetooth so I'm thinking it would be helpful to have something to plug my phone into at the helm. Also I'd like to listen to satellite radio and I already have a GM51 connected to a Garmin 4212 so hopefully there's a way to connect the GM51 to whatever system I wind up with. I'm open to suggestions so fire away. Thanks, Ed.