The more power, more fuel is needed... So cant reallly lavve one whiteout the other. I am not snotty or anything, maybe a cold air kit duno about availability for a set of headers....then a full exhausr.... then a proer tune.....you might notice the power gain
More HP means more gas. There is no free lunch. Your better off leaving it alone. It is just a family car not a performance car.
Messing with injectors and seeing any power gains means custom cylinder head porting, exhaust headers, camshafts and dyno time with someone programming the ECU.
That will cost 3 times more than the car is worth and after that the transmission will not take any additional real power boost.
Start saving for a Camaro if you have the need for speed.