Would you change anything in this setup for 450ish fps(by change I mean barrel diameter/length, bucking, other mods). Prommy purple bucking(no mound removal), prommy 6.03 509mm barrel, white h-nub (glued down), shimmed hopup, barrel spacers. Also I do not know of a good metal g36 hopup unit in the states, what bb's (weight/brand) would you guys use. I am going for the best accuracy possible within the fps limits and reasonable price (no $120 barrels and such).