Regardless of which version of Trilogy you have, you can use an LP tank. LP tanks output at ~450 PSI; Trilogies with regs are set at ~350 PSI IIRC, and will sweetspot much lower (my stock Competition sweetspots somewhere between 200-250 PSI). Since it's a mech gun you don't really have to worry about having a higher output. The only reason you want a higher output in the first place is to give your tank room to recharge during fast firing. And if it's a Sport, they can run down pretty low without changing springs as well.