Because it is still capable of maintaining the proper A/F ratio I have seen plenty of Zs on the dyno and they never run out of fuel with stock injectors and stock turbos......Yes they are almost maxed out, But the stock turbo can not move more air then the stock injector is capable of keeping up with. My point is it will not make any more power.....It can not because the fuel ratio can be adjusted in the correct range. Most people do not put race fuel in their cars so they certainly do not need larger injectors. Going with any size larger turbo , A larger injector will be needed. If you have bad injectors and plan on upgrading turbos some day , Installing larger injectors is fine and there is no down side.....But thinking you will make more power or make it safer with larger injectors with stock turbos is not going to happen.