[nayrb]

when you get bigger injectors, does it let a little bit more fuel in (without messing with any fuel mapping or anything) or is it just able to put out more?

 

[Vamp]

It will be able to put out more fuel. You can probably run 20cc more over stock without issues, but any larger than that and you'll have issues with running rich. You'll need a fuel management system for those, but it's useless to put them in unless your putting more air in the engine via a turbo or supercharger.

 

[Boosted2.0]

when you get bigger injectors, does it let a little bit more fuel in (without messing with any fuel mapping or anything) or is it just able to put out more?

Larger injectors spray more fuel for the same injector pulse duration as a smaller injector. They are rated in CCs - thats cubic centimeters of fuel per minute. The larger the rating the larger the amount they will spray in any give time. They cannot be used without a standalone or a very good piggyback to compensate for the different size.