Welcome to BHQ & congrats on the banshee purchase
I would change the gas, trans oil, and coolant for sure. If your wonder what oils to run, in the gas I run Klotz R-50 @40:1..trans I run ATF type-F, and coolant I just run 50/50 Prestone.
Make sure your jetting is correct to avoid any motor damage caused from running too lean. Start rich and work your way down. Also make sure both carbs are synced with eachother (the slides open and close simultaneously with one another).
Having the owners manual will come in handy for sure.