you want more fps... may i ask why... the broxa is already shooting 380-400 witch is more than enough! consider a good quality inner barrel like prometheus 6.03 and a good quality hop up rubber with these two things your broxa should have more tight groupings , might want to consider a prometheus m110sp sring and bearing spring guide for improved fps consistency
go check at
www.airsoftparts.ca
edit d'ahh they dont have prometheus inners this one is great too
http://www.airsoftparts.ca/store2/in...roducts_id=460 i have one in my jg mp5 and it performs really well!
be sure to shoot heavy bb's to get maximum range and accuracy , i'd say minimum .25g best .28g