ok, i know i'v posted this a long time ago, but get on the search function and search my name on here or search here for the ULTIMATE ACI UPGRADE post, it tells you what you can use. I posted it a while ago, and with talking to people from ACI before they went out of business, ESP frames will fit it, spyder top cocking bolts or bob long bolts will fit it, as well as spyder triggers (trigger hole for pin might have to be drilled out a little), can do a magnetic trigger mod, can mod the solenoid, can also modify the front block for more flow and better pressure, and if you want to upgrade the board change out the grip frame for a spyder e-frame and get your hands on a scenario dreams t-board, then you can mess around with the origional aci frame and practice your mods on that then go to a spyder frame, you can also do some custom paint jobs on your markers too if you'd like, but it's all up to you!
Blue /Black '05 Proto
Red/Orange Old School Defiant
Black ACI Felon that has been upped by myself. Shaved trigger, rounded detents, red painted accents, ACS bolt, soon to have an upgrade for the solenoid, and getting a 50g microswitch
TEAM IKU- out to dominate