2003 F-150 Heritage.

[Saber123316]

So i have a 03 Heritage, 5.4 4r70w 4x4. AFE stage 2 intake and magnaflow cat back exhaust.

I have been contemplating upgrading to a larger throttle body and a lightning MAF with the custom tunes will this lead to more usable HP from these 3 combined mods?

also will I need custom tuning for longtube headers?

AND

If I go longtubes into a single 3 inch Y will I belimiting horsepower production in the future?

goal is to have a 14.5 second truck in the 1/4 mile.

thanks for your inputs