The main reason people change the cam is that the stock cam is not a "performance" profile. I'd leave it stock until you get it running right. There will be MANY variables you'll need to take into account, so why add another with a new cam? Same thing with the coils, keep it stock until you get it running right. That is if you are keeping the EFI setup. IMHO I'd get the wiring harness from the Explorer and use it, at least until you get it running. THEN do any mods you want.
Another option is to remove the Explorer controls and use all Mustang EFI parts. Mixing and matching Explorer and Mustang parts is a recipe for frustration until you have a baseline from which to make mods. Also, get a wiring diagram for the Mustang & the Explorer. Don't try guessing what each wire does.
Another option is to remove the Explorer controls and use all Mustang EFI parts. Mixing and matching Explorer and Mustang parts is a recipe for frustration until you have a baseline from which to make mods. Also, get a wiring diagram for the Mustang & the Explorer. Don't try guessing what each wire does.