If you use the 19# injectors you will need a custom tuned chip to make sure you don't run rich. You have to tell the PCM you're flowing more fuel, and the chip does that.
Since you'll need a chip, I don't beleive you have to mess with the MAF. StreetFlight burned me a chip for my 3L and the 19# SVT injectors I'm using for use with my stock MAF.
I can't remember of the SVT MAF actually is larger than the stock SE MAF.... maybe someone can answer that for you. If the SVT MAF isn't larger, then I don't think there's a point to using it instead of your stocker.
