Bluerooster,
You really have to look beyond the exterior paint job and engine bay to see the differences between various manufacturers cars.
Some replicas use a Ford 9" or 8.8" rear end with basically stock suspension and brake componants while others use a Jag, T-bird or custom IRS set up with coil overs, custom A arms, high quality four piston brakes, pin drive wheels, etc.
On some cars you'll find a stock mustang gas tank while others sport a fuel cell.
Some cars use a Mustang II front end while others have full custom set ups.
Some cars have cheaper or stock gauges while others may use imported period accurate gauges.
Some cars have vinyal interiors while others use leather.
Some cars use all Aeroquip fittings and stainless braided lines while others use rubber hoses or stock lines.
Some cars have thick bodies with rolled edges, others don't.
Some may feature
oil coolers, stainless puke tanks, brake bias adjusters, high end electronic ignition systems, heaters, tops, and stainless exhaust pipes.
Anyway, the list of little things is what adds value to a car.
They all look pretty much the same from a distance, it's when you get up close and start comparing cars that you see a difference.
Cheers
Jim