I found the first few lines of your comments amusing. I feel the same about my 242 as you do about your boat...love it except for the stereo and in my case, the Vision dash. Maybe they have drastically improved the Vision from the 2012 models to the 2015 models, but I went through the first summer having issues with both devices. The Polk stereo definitely was not up to Supra standards.
As far as the Vision, it had to be taken out and sent back to factory to download new firmware to correct some problems. Haven't used it since so I'm hoping it will be ok this summer but I never used it for controlling the audio. Very clunky interface. It was ok to monitor gauges or look at GPS but that was about it. Hoping to finally be able to adjust ballast timer and not have to manually fill and empty this year.
The Polk stereo was all stock and worked more or less when the transom remote wasn't shorting it out or the amps did not get too hot and keep shutting off. The biggest problem I found was that we did not have any separate zones and when you cranked it up, you still could barely hear it while surfing but everyone in the boat was holding their fingers over their ears. Also, not having bluetooth and hooking up USB was a bit annoying.
So, mine just got a gut job and I started over completely with all new. I went with a Fusion UD650 3 zone head unit and just two new remotes eliminating the one in the passenger area. We only use the one by the steering column and found it was the easiest way to control the stereo and actually in a decent place to make quick adjustments. I can't answer your question about integration as I did not focus on that aspect with my new equipment. I can see how that would be important to you but I like the display on my new remote with the larger LED screen now. I will be able to see things easier and it's not just play, pause, skip buttons. Honestly, I don't know if I will see any connectivity on my Vision in regards to the stereo now. Will know soon enough.
As far as rest of equipment, I chose all new Wetsound SYNDX6 and SYNDX4 amps and all new Wetsounds speakers. I had originally 4 six inch speakers in aluminum cans on my S-bend tower. Two were eliminated and 2 replaced with the REV8s. The interior also got 6 new REV6s with built in LEDs along with 6 Wetsound speaker rings and a RGB controller.
The old Polk 10" subwoofer (without a box) got replaced with a JL Audio 12W3 with custom box behind it. A few custom touches later and this thing rocks. It is very loud and can't wait to jam on it. I have the 2 bow speakers as a zone, 4 rear interior as second zone and the 2 towers as the third.
Now, as someone surfs, don't have to worry about causing deafness to rest of crew. Posting a few pics.
Good luck with your install. Anything will be better than the stock Polk for sure.
All the old stuff.
https://i.imgur.com/m2ErmBz.jpg
Some of the new stuff.
https://i.imgur.com/7wNdPlW.jpg
https://i.imgur.com/LY44itn.jpg
https://i.imgur.com/JNJ8RYf.jpg