Have totally reworked the insides with a madbull m130 non linear spring, metal teeth piston, metal silent type piston head, dual o-ring cylinder head, metal air nozzle with o-ring. Already came with the nice neo magnet blue ultra torque motor. Reshimmed, regreased, and rewired inside all the way thru with deans 16ga ultra wire. Has a very nice mosfet with burst controls.
The s-system is known to have small compartments for batteries so don\'t know why i tried it this way, but works very very nicely. There is two batteries in the handguard. And trust me took alot of modification and wiring to make this work. But one is a High Grade 11.1 800 mah lipo. The other is a High Grade 7.4 1400 mah lipo. Both fit in the handguard. The toggle switch i wired and installed in the handguard allows me to switch from off, to battery 1, to battery 2. Depending on what kinda fire i want. (controlled burst , or fast cover fire) switching between the two types makes the difference of 14rps to 21rps!!!!