I'm in the process of buying an '86 LTD (4 door Fox Body) & planing to do the 5 lug swap as well. I found it to be cheaper to just find a 94-95 Mustang project that needs engine work. I just picked this up two weeks ago for $600, the engine was taken apart and left to sit but it has almost everything for me to use for a manual & 5 lug swap, brake upgrade, & 17" wheels. Really have to keep an eye out, but it seemed worth it compared to what others out there are charging for the spindles alone. It was listed for $1,000 at first and said he was firm but after getting some new pic's showing it parked and covered in calked on pollen with the engine in pieces with rust on the pistons, cat's cut off & a small dent behind the drivers door I was able to talk him down. Found it on Facebook Marketplace, seems to be the only place that I can find project/parts car's at reasonable prices. Just have to filter through all the sketchy people selling their car's without titles or lack of communication skills.
It's not pretty, but as soon as my ruptured tendon heals I plan to give it a good wash & wax and sell off the rest as a project to someone else to recoup some money. May even keep it and build it as an autocross project.
I was almost tempted to just stick with 4 lug as well, mostly to keep it period correct but cost wise it was just cheaper for 5 lug. The ones I like are the LMR Mesh & TRX, but that would have pushed my budget too high & finding decently priced used 4 lug 16-17" wheels is getting difficult.