Since you are NA I don't think you would have maxed out the stock injectors yet. Does any of your computers tell you duty cycle? If it doesn't need more injector more injector won't help anything.
Watching the fuel trim go to positive %18 - %20 percent near WOT it just seems that a little bigger injector might be wise, plus if I upgrade to better intake, heads exhaust anything like that down the road I would like to already have the extra fuel. I am not too worried right now but down the road I want to be covered.