Well... not really.  Liquid CO2 at room temperature puts out 850 psi of pressure, so it's "self-regulating" - you don't need a regulator.  You only need a CO2 regulator (aka stabilizer) if you're dropping your pressure down to the low-pressure range (if you're using a Low Pressure kit, for example).  Some people use the Palmer Stabilizer at the regular High Pressure range to "stabilize" the CO2 (somehow the stabilizer helps prevent liquid from getting past the stabilizer... when liquid gets past, you get velocity spikes, etc...)

what will running my gun at low pressures do for me nywyaz? i mean whats the point? so do u think that i should get a stabilizer and the lpk or hpa.