That harness is awesome. I got the basic harness that is not specifically designed for the bronco from rjm and could not be happier. It took a little more work than the harness you are looking at but was a piece of cake overall!
I bought my metal fuel line at ace hardware. Got a 20 foot roll for around 20 bucks. Works perfectly.
Maf needs to be from a 89 to 93 mustang. It also depends on your injector color. Chances are you are just running the 19lb injectors so most mafs from those mustangs should work fine. I may have an extra one laying around. I will look when I get home and let you know.