is there a legitimate way to improve performance for a 2007 F250 5.4l gas automatic 4x4 crew cab long bed?
I don’t think there is much you can do that would do anything but marginally improve the performance or cost a lot of money on this or most of today’s motors. The biggest problem with performance is, you have a 3/4 ton 4x4. I hope you don’t expect better economy, and the truck was not geared to perform like a car. Trading for a modern diesel ( gmc), the 6 l from Ford or drive a car would be the only options that make sense to me. Nothing is cheap. IMHO, once you decide on the 250, might as well get the biggest, baddest motor to begin with and hope gas prices go down.
Are you looking for better “performance” as in more power (for towing, hauling, etc.) or better fuel economy?
You can add on a supercharger. It will require premium (93 octane) fuel but MPG should remain about the same, unless you “use” the supercharger a lot.
A supercharger will cost you mileage no matter what, it’s driven by the engine.