Sorry, delayed responce. Windscreens? I never use them so no help from me there.
Rollers? I installed stock weight sliders and couldn't be happier. Actually tested before and after at my local 1/8 mile drag strip, stock 11.358 @ 60.008, sliders 10.531 @ 63.51. You can't get more performance gain for the money. Installed the sliders about 12000 miles ago. Just replaced the belt at 15.4K miles and checked the sliders. They were perfect. I've used sliders in several bikes and never had one "flip". It's my belief that the flipping happens during the installation process. You have to hold the variator between your thumb and two fingers when sliding it on to the crankshaft. Do not push it on using the inner spacer. OEM tires? Get your moneys worth out of them then maybe try something different.
I bought mine new, first new bike for me in 18 years. Have been very happy with it. Mine did have a couple minor issues. Belt would slip when ridden in wet weather, something I do very little of so no big deal for me. The other issue was a dragging rear brake. I ended up finding the problem and fixing it myself. Ride the bike for a few miles without using the rear brake at all. Stop and feel the rotor. If it is hot you probably have the same problem I had. Also, if dragging you will accumulate brake dust on the rear wheel.
Enjoy your ride.