Hello Jason,
Welcome to the site. Both filters are good quality. The Uni is considerably cheaper. You need to purchase the oil with the filter for the initial soaking.
I agree with what the others stated. Start simple. Make 1 change at a time. Make sure you keep up with the carb jetting as you increase the air flow into/out of the engine. Removing the snorkels (there are 3 on the early Americas) required that I up my mains and shim my needles. If you cut the bottom of the airbox, you might have to increase size again but run the small risk of getting water into the airbox during heavy rain riding. If you do open up the bottom of the box, it is reversible.
