I have been using the Air America Vigilante and it works well. It has a fast recharge and works well most of the time. Problems: I have had to replace the pin valve in it once and the pin seal 3 times. You WILL be able to reg down your gun to about 500 PSI without mods. If you add a high flow valve pin and volumizer you can get down to 375-400 and put a lighter main spring in to reduce the recoil, that's were mine is right now. What ever reg you get make sure it has a guage port that will indicate output pressure of the reg, most reg ports a just on the other side of the input line and show input pressure.