2000 F-550 looking for best power/fuel economy.

[4drbrnko]

I've tried to read through everything before I started asking...... honest.

The truck and mods so far:
2000 with 101,000 miles, all services documented by original owner.
Gauges so far: tranny temp, pyro with probe installed after turbo(it's where it was installed prior to the 4" dp, I've heard this position will give readings 200* on the cool side?), Boost. I'd like to add: true engine coolant gauge, as well as monitor fuel, oil pressure and temp, rear end temp. Does the gryphon support add on sensors for any of this?
4R100, remote mount tranny cooler with fan, external filtration as well.
4.88 rear running 245/70R19.5 tires for better stability as well as a slight rpm drop for the freeway. (4.30 gears coming once my buddy sources a carrier)

Engine:
I've done a 4" dp/and exhaust with a flow through muffler that exits just in front of passenger tire. (couldn't get mandrel bent system to exit behind tire due to the air ride suspension)
Warmup valve delete(housing was leaking oil)
High pressure oil crossover line.
203* thermostat
Engine coolant bypass filtration
I haven't done the intake air heater delete, some say do, some say it's not enough restriction to matter?
Fuel pressure regulator bump to 75 psi will be done by the weekend.
The rest of the fuel system is stock, future upgrade to FASS possible if it will help with fuel economy/longevity of engine?
Wicked wheel upgrade going in Tuesday to help the turbo "flutter" that showed up after the 4" exhaust and S&B air Intake.

So far, using a borrowed Predator I've been able to hit 17.6 mpg with an empty truck, no towing. MPG calculations run off of true gps miles using same station/same pump for every top off.
Mileage was the same using the 100 horse and 85 horse program, neither of which could use when towing heavy I know, just shooting for highest mpg's when empty.

I've got my engine oil sample kits and will start a regular testing program to monitor engine internals.

My main questions:
1. What other modifications can be done to help with mpg's/engine longevity?
2. Since my buddy won't let me keep his predator forever and I don't care for flashing my truck when I want/need to change settings. What tunes/programmer should I look at getting?

If I've left out any vital info let me know?
Thanks
Jeff