I got my 2018 RT Limited in March, and have a little over 3000 miles on it now. During this time I was able to figure out what were the most important things to do.
I think one of the best investments I made was the BajaRon anti-sway bar. Really stabilized my ride. I also added wide-vu mirrors to avoid the blind spots. It is amazing and highly recommended. And of course a RAM mount for my phone - how can you go without one?
I then added a cramp master to help me with the throttle because I noticed I'm getting a little numb in my fingers, especially when I do twisty roads that require a lot of twisting on the throttle. for highway I just use the cruise control - it's amazing.
After doing a couple thousand miles, I realized it will be so much easier on my back if I added a backrest. I added a Can-am backrest and never looked back. It took some adjustment to the backrest to get it right for my height but once I got it right it is amazing.
A couple of thousand miles also alerted me to the fact that My butt needs a softer surface to sit on so I added a butt pad by Alaska Leather.
Also looking for safety measures with my breaking lights, I installed a Vololight license plate frame. It recognized deceleration and flashes even before I hit the brakes (I like to slow down using the engine and gears). I am also adding some break/turn/stop LED lights to my rear trunk soon.
On my recent trip (about 1100 miles), I noticed that the belt vibrates around 70 mph. At first I thought there was something wrong with the bike but friends on one of the Facebook groups helped me realize what it was and I ordered a vibration dampener which one of the group members will install for me shortly.
I also installed Leadlox because when you travel with a lot of luggage, there is no room for your helmet in the Frunk and you do want it secured.
As you can see, the list is endless and there are so many things you can add. This was just my current list. I know it will grow as I put more miles on Polar Bear.