Just recently bought first RZR

Hi, we just bought our first RZR!
I Scored on a 2013 LE .
I owned a VW sand rail for 40 something years, then bought an ATV for my ole lady and a dirt bike for myself. Sold the ATV last year and bought a Teryx. After riding the Teryx a few times I knew it wasnt want I wanted, so I sold it and found a RZR ! And I love it !
A couple Questions I have; It needs new tires, still has the stock tires on it, I was told I could go one size bigger Im assuming to a 26in.? I still want to be able to run it on the 50in. trails.
Also I would like to get some more storage bags for it , thinking of the roof bag , the bag that fits in the bed of the razor. Maybe someone could give me some input on whitch ones they like or disliked.
Thank you !!!