If the existing injectors are not maxed, changing injectors will give you nothing. If you have a stock MAF an upgraded MAF will help but there is no point going any bigger than 70mm with that intake. The inlet is 65mm. I highly doubt you'll pick up .3 from a MAF swap. If you're using a calibrated MAF for bigger injectors, you will absolutely benefit from a tune. Calibrated MAFs work but as far as the computer is concerned, the load reflected in the computer isn't really accurate so timing is affected. It's how the calibrated MAFs work unfortunately.