you'll need to replace the foregrip with a regulator to bring down the air pressure. From there you will need softer springs for both the valve and the main spring IIRC. beyond that because you will be running a lower pressure you will want to open up the air passages out of the valve since you'll have to compensate for the drop in pressure with an increase in volume. I would also fit the biggest volumizer I could find on the front.
This is all me running on the assumption that this is a stacked tube blowback gun (a la spyder). If it uses a different method of operation then the above modifications would be pretty useless. Additionally a low pressure reg would do you no good because LPR's are used to run pneumatic rams, which your gun probably doesn't have. In your case running at low pressure would mean the high pressure (while still being called high pressure in this case) is significantly lower than it would have been in stock form.
"hey! I found the problem!"
"Is it an o ring?"
"No, It's ALL the o rings!"