Do not buy a CP trigger. They have just as much play as the stock one. I returned mine the next day and the guy said that they arent the best. Ive got the lurker bolt upgrade and the lurker poppet upgrade. If you search for it youll find a large thread about it. As far as asa on/off, save the $80+ and buy a trinity one that screws onto the tank and gun. It only add about 1.5" to the length and is very easy to use. You can find one on ebay for $20. I would get a freak kit for sure, its helped my gun by allowing lower pressure to operate. The foregrip extender is a nice upgrade as well, people who i've spoken to say they love it. its $33 on ebay. Dont change the feedneck, the stock one is very good in gripping the hopper and the lever isnt too hard to operate. Anything past that, grips, board, detents is all users choice and should be purchased after youve played with the gun for a while and tried other people's guns that have those upgrades. Anyways, hopes this helps.
Say what again. I dare you.