The new piston is an element one, isn't it? Don't use it, their piston body are made of plastic, even their full metal teeth, they are made of cheap metal.
Few suggestions:
1, Don't use full metal/steel teeth piston, they are gonna wear out your gears really quick, get a nylon fiber/polycarbonate piston with 1 or 2 steel teeth.
http://www.redwolfairsoft.com/redwol...l_Gear_Set.htm
2, no need to downgrade it to m110, try find a branded m120 spring. As a matter of fact, m120 is the perfect match with good balance of fps and durability.
good luck
Tank