the best way to see if your engine needs bigger injectors is with a scanner. under full throttle at 4500 rpm, look at the injector pulse or "on-time". if it is anything close to 13 milliseconds. you need bigger injectors. If you do the math at 4500 rpms, the engine is turning 75 times a second. convert that to milliseconds and its 13.3ms. which means if the injector is on for 13ms, it is only off for 0.3ms. which is close to being open all the time. time for bigger injectors. the pcm will compensate for slightly bigger injectors