Open it.
Take out the first barrel assembly.
To get the air restrictor out, seperate the two halves of the barrel assembly. This requires a little bit of prying open with a knife, because its glued together. If you find it isn't comming apart, soak the area with some boiling water for about 30 seconds and it should loosen it up. (One of my barrels I was able to seperate with just a knife, but the other one needed the boling water)
When it's open the air rectrictor will come out, just clean up the remaning parts for smooth unrestricted air flow
To get to the second barrel unscrew this pannel.
there's the second one. remove it's air restrictor the same way as above.
with both air restrictors removed, cover the small hole in the barrels with tape, and wrap teflon tape under the o ring to increase the seal.
then wrap some tape onto the plunger, where the spring sits. use enough so that the spring can rest on it. this allows the spring to compress more.
reassemble. and make sure to lubricate the O rings.
with these basic mods, i got it to fire 11 meters flat with the stock dats. up from about 7 meters it fired stock.