Re: spare tire
Best place for spare tires is craigslist (get creative on searches) and Junkyards, like a u-pull-and-pay.
I got a complete spare kit for my dad's Kia Soul (turbo model without spare) for $35 including all trunk accessories, foam, jack, tools, mount, even the screw in tow hook. Someone was selling parts off a wrecked one.
Search for parts cars/dismantling type of ads. Also learn up on alternate donor cars, and what diameter spare fits over your front brakes.
With a mustang, maybe a Charger/Challenger spare would work, same bolt pattern still?
1967 El Camino Malibu - Deepwater Blue
ZZ4 350, FiTech 600 complete!,Roadmaster tank, 700R4, Underdash A/C in progress, JGC Steering, 1990s truck serpentine.