Just posting a couple FFR mods that may be helpful to you. I did them on my build and highly recommend them.
Door latch mod:
Door latch mods for greater reliability and function This is a cheap and easy mod and will prevent you from damaging your door latches and they will operate smoother. HIGHLY recommend!
License plate mod (aka: Jeff's License mod)
Mk4 rear license plate holder & "t" handle
Headlight mod -
Headlight tabs and clips
Fix for loose headlights
Custom aluminum Fan Shroud -
Made my fan shroud and mounted the radiator
’65 Mustang Ignition, Lights -
Mustang Wiper switch parts, I think I'm missing something
Vintage Switches from 64-66 Mustang?
Implementing these mods will definitely add time to your build, but they were some of the most rewarding and custom touches you can do. You may get great pleasure and recognition out of some of them, and others may go almost un-noticed!
Add the PS Footbox mod to your list! The passenger will GREATLY appreciate it and they don't even know it! I took my 6'4" friend out for birthday lunch today and his feet fit side-by-side and barely touched the end of the box. with the original PS FB, he would have been uncomfortable with his feet lapped over each other and knees bent up to the dash.