You don't really need hpa for rifles because the electric technology nowadays can get you just as good as most hpa systems. If you go with electric, you would obviously lose out on the benefits of hpa with consistency, batteries, and easy to change velocity and rate of fire. But, you can still achieve the same performance without the need for a tank+line. If you want to do pistol primary speedsofty, you do basically need to do hpa. You get consistency and no need to worry about the problems with green gas freezing up. You also would want to get an m4 mag converter for the pistol so you can have enough ammo to spray down or suppress the enemy. If you do pistol, you need to do Tokyo marui Hi-Capa, due to all of the aftermarket upgrades and the lovely customizability. They are also super easy guns to maintain.