M249 SAW Proprietary parts?

[prepaidpwnage]

I am going to be upgrading my friends ECHO 1 SAW soon and I was wondering if there are any parts that are SAW specific. Like the long cylinder heads that the G36 use ect. So, particular I would be upgrading the Cylinder head, Piston, Piston Head, Air Nozzle and the Spring to something that shoots 350 or so.

My plans so far are as follow:
-G&P Polyacetal Piston (my ARES G36 loves it)
-Systema Duracon Piston Head

I do not know what type of Cylinder head (Ver. 2 Ver 3. other?) and Air nozzel are used. Suggestions are well appreciated.


And I live in the States, if that helps me get any different parts at all( I feel bad for you Canadian Gents and your airsoft import things).