Std feedneck is poor, std barrel is poor, std trigger is poor, I would forget the SP Q-Lock, still won't take an unsanded halo/empire, go for a CP clamping feed neck, almost any barrel kit is good, though the Freak is not as great as an Evil Pipe set or similar, Stiffis are a bit delicate! A CP Roller Trigger is an almost must have upgrade for an Ion.
Get rid of the duckbill and put a decent on/off on it, will save you grief/blown O-rings and a better setup.
If then you don't want to change your marker then look at a board upgrade, really I would steer clear of cosmetic things like bodies etc as they usually add weight, edges to catch paint on and no performance iat all. Sticky grips and a decent fore grip/inline is where I would stop. For the record I dont have and have never had an Ion, but have fixed them for mates and seen them spend loads on them to no advantage, and then buy a better setup!