even though the estimate rather is overstated (quite understandable as the restorers are not non-profit ventures) with quite a bit of details/fragments/processes missing, i would like to break things down that could lead to reasonable resto costs;
stripping the car of all mechanicals/electricals/trims/interior etc. to a bare shell
stripping body paint with paint remover
undercarriage stripping (media blasting)
suspension stripping (paint remover/media blasting)
rust repairs and panel beating
rust treatment & prevention such as (POR15, Fertan, Dinitrol etc.)
seam and other sealants
cavity waxes
rubberized coatings/road chip
insulators/noise reducers/sound deadners
powder/zinc/chrome coatings etc.
paint systems (can cost serious money depending on personal choices)
choice of painting techniques
interiors and other trims (again can cost serious money depending on personal preferences)
extent of mechanical/electrical repairs (again can cost serious money, for instance consider using top rated engine building lubricants/sealants/gasket makers etc.)
refitting of everything to make a shell back into a car
finishing and refinements
each and every single variable above would result in different project costs and is potent to turn any resto into a 14k gold dip