The trucks are just cammed differently than the mustangs, they have a different firing order. The ecu's are pretty important mostly to match up firing order, they can be tuned to work around the cam difference. I dont know if you figure it out yet, but you can ditch that intake and use a gt-40 intake from a 5.0 exploder or merc mountaineer. A good port and polish on your heads annd intake will make a drastic improvement over any bolt on part.
A word of advice, 5.0 iron blocks work insanely well with offroad h-pipes, while the modular motors like the x-pipes alot better.
Awesome build, oh yeah, the difference between cams in the cars and trucks is the trucks are cammed for low rpms' and torque and cars are cammed for higher rpm and hp.
Your application will tell you which you need.