Also, the SE has offset bottomline holes so you wont find a on/off that fits without modefying the gripframe or build an adapter.
My own experience with the ACS bolts is that they are more of an "anti ball chop" then an "anti chop bolt". Get an alamo city paintball bolt or run the stock one and youll be fine.
I would sugest getting a better barrel and some rubber grips, and thats it
In sweden we ride polar bears to work, drink our coco from steins, sharpen our battle axes with the bones of our enemies and bork, bork bork, bork.