Any of the Mustang parts suppliers, such as those on the right of this page, Custom Mustangs, Harrys in Sydney, National Mustangs etc. will be able to supply the correct hardware and post or courier them to you.
The original style bolts for the guards have captive serrated washers that cut up your nice new paint under the bonnet. There are stainless alternatives with a rubber or fibre washer or something if originality isn't crucial for you.
If you have a manual steer box in the car and add an electric power assist unit you still have 19:1 ratio, its just easier to turn it all that way. The Borgeson setup makes it 16:1 like an original power steering car and is a better idea in my view. If you go electric you'll need a bigger output alternator to keep up with it.
