I dont know if it has been changed in the year or so I bought it, but the Madbull ultiamte hopup never worked right for me unless i had a madbull barrel and hopup rubber in it. somehow they managed to get it to only properly fit madbull products in it.
I suggest getting either a modify accurate hopup or a king arms hopup unit, promethius barrel, and a guarder clear hopup rubber.
for a motor if you can find one a G&P M140 is what ive had the best luck with, if you can't a G&P m160 or 180.
mags, MAG or PMAGS.
for a battery box
http://www.airsoftparts.ca/store2/in...oducts_id=1247
with
http://www.airsoftparts.ca/store2/in...oducts_id=1648