[sandworm101]

3d printing isn't as useful as people think, not for old cars. The parts that wear out are the parts that are put under some sort of load. You cannot 3d print a shock absorber. You cannot 3d print a connecting rod or bearing. Sure, you can print out a plastic widget for holding a mirror in place, but you cannot print out the actual mirror when it breaks.

[kenhwang]

Porsche is already thinking of 3d printing piston heads since their research is showing it's stronger than if they forged it.

I don't think there'll ever be a need to 3d print shock absorbers or bearings, since those tend to be commodity wear parts and there will probably always be compatible modern variants (or if you look at some parts guides, many current cars still use the exact same basic parts from several decades ago).

Engine blocks and major large internals like conrods or more commonly needed transmission internals are the parts I think will be most difficult to keep stocked.