Yeap ics-127 is fine for M120 spring upgrade it got the turbo 3000 High Torque motor and metal bushings
http://bunker.pt/index.php?main_page...08&language=en
Full metal Body.
- Modular Metal Gear Box.
- M100 Sping (300 - 330 FPS).
-
Motor Turbo 3000 High Torque.
- Metal R.I.S. System.
-
Steel Bushings.
- Cylinder Crane Stock.
But... @ 320 fps (avrg) if you go for a prometheus 363mm 6.03 (about plus 20 fps) and do a blueprinting job on the upper gearbox (about plus 15 fps)
you are @ 360 to 375 fps without
any un due stress on your battery and gearbox ((that extra 20 fps extracts a heavy toll on the gun with marginal advantage when you think about it plus you get 25 to 35% more play time (read "SHOTS") from your battery
So if you upgrade de barrel, replace de piston and head with good stuff... and your set for a trouble free airsoft career...
Cheers
Pete