Check the fuel pump , if its working fine no point changing. No point going bigger fuel pump or bigger injectors with stock ECU. It wont gain any power. Nice headers and exhaust will give a small gain - maybe around 5-8%. A good cold air box will give a tiny gain, and Im not meaning a pod shoved onto the AFM. From there its the stock ECU holding you back. Options for aftermarket are limited while its an auto. WOLF V500 can run the auto so that may be an option. With an aftermarket control unit then things like cams come availiable. Another option would be to buy a VVti with auto and put that in. Good power gains and cheaper than making the same power with the early motor. Cheers