You should get some one else to install it.
However... I don't think I've looked at the advanced model of the G&G M4 yet... I looked at one that had all the silver wiring and everything else... but it just had the same shitty piston head.
Compression issues will make your shot to shot FPS vary quite a bit, this will greatly effect the consistency of your gun.
Gun Technician and Tuner
Well versed in every AEG version and all major gas and spring systems.