I'm not sure is any of the Ford's are 2 jets. I like the Design III's better then the Design II's which aren't Mustangs. Do you have a YJ or TJ, since that makes a difference when choosing injectors. The 4.0L TB is a good idea. You might also consider picking up an ebay TB Spacer as well. They're usually around $35. Consider the Performance Distributor Firewire kit. It's very good and cheaper then Jacobs or MSD. You get a cap, rotor, wires and a coil with the kit. It will allow you to regap the plugs to .065" instead of .035" which will allow for a more efficient burn.
Oh when choosing a radiator, go for the all metal. The plastic tanks tend to leak over time. The metal radiators don't have that issue.
Radiator is stock replacement, getting it from a buddy so really can't beat the price, mine is just smoked.
93 YJ is what this is all going into. I am not sure what is the difference between Design II and III or anything else for that matter, just started really doing the research this week so still learning.
4.0 TB is on it's way $15 from another buddy, can't beat that.
I was looking at TB spacers, if I can find one dirt cheap I will do it, otherwise I can't afford it.
I already have stock replacements for the wires, cap, rotor, plugs. They have been sitting in the garage staring at me for some time now.