M4 help & Advice please?

[carvolution]

Hi guys and gals,

I own a JG M4 S-System with a ver 2 gearbox, and last weekend it stopped working. No noise or anything, i pulled the trigger and nothing, so Im guessing its something wrong with the trigger, so I have left it with a friend to look into it.

But while is buggered I thought I might as well do a little upgrading!

I have already fitted a madbull python ver 2 6.03 barrel and a systema high speed motor.

Im thinking of upgrading the hopup unit & hop up rubbers, but my questions are as follows:

What is the best hop up unit to put in it
What is the best hop up rubbers to put in it
And if the trigger is to blame, what should i replace it with as it already has a MOSFET trigger out of the box being a S-System?

And help and advice would be great as im still new to this upgrading bit! And im after range and accercey as the power is 330FPS and thats great for all sites!

Thanks Everyone!