Am I Missing Something

The pulleys really don't do that much. People will claim "they free up 10-15hp", I highly doubt it. If you do get pulleys, make sure to get ones like Steeda or any other one that replaces the crank pulley. The "piggyback" style pulleys have been known to cause issues.

The rails....you don't need them. The stock rails are good for a long while....unless you just want to dress it up. Unless your injectors are clogged, I don't think you will need to upgrade the injectors with the bolt-ons you have here.

I am also on the fence about the strut tower brace. I had one, but I did a lot of suspension stuff at the time of install. The Steeda G-Trac kit that I did made a huge difference. Later when I took the strut tower brace off....I didn't notice much change at all.

The stock fuel filter is fine. Even at 500rwhp, I was using a stock type replacement fuel filter from autozone.

What you are not looking at is the exhaust. If you live in a place without emissions and inspections, I would say an O/R mid pipe. Short of the supercharger, the main things that I noticed a difference with was the gear change, and manifold back exhaust.

My order of things would be.....

Springs
CAI
Exhaust
Gears (if manual 3.73 minimum, but consider 4.10s....automatic 4.10s!)

You could swap exhaust and gears, I love the gears, but gears on a car that sounds like a glorified lawnmower never appealed to me. I

500+rwhp and never anything but Motorcraft OEM fuel filters with no problems