THIS.

I have a 03 king ranch screw 5.4 i bought recently with about 93k on it. prev owner installed a K+N CAI and flowmaster dual exhaust. bought the sct livewire from MPT (More Power Tuning) with a choice of 3 tunes. currently running a 91 oct performance tune with the firmer 'street' shifts. All I can say is love it! My butt-dyno gives it 2 thumbs up. I love the bump in performance, its def noticeable 0-highway speeds, and even though I haven't actually calculated mileage it has definitely improved also.