One thing I did to my 1911 was change the stock piston head over to a nine ball vented piston head. It made a nice improvement with gas consumption. I was able to get a few more shots out of the mag, which is nice because the 1911 mags dont hold much gas.
I installed the small spring, but ended up removing it because it made the gun a gas hog, without giving much increase in fps.
http://www.airsoftparts.ca/store2/in...roducts_id=345