potentially you can 3d print Inconel and make waste gates. they 3d print turbineplades for jets.

however from my experience they will be much more expensive than cast ones if done in some small volume.

Not without engineering substantiation. Depending on the part and the criticality of that part it can be a minor or a major change. If it's a major, that's a full blown FAA cert project.

But, keep in mind, Aerostars have AAC ( https://aerostaraircraft.com/) providing support.

Other cabin class piston twins don’t have the same level of parts and engineering support.

This is the understatement of the year! John Jurkovich in parts and Jim Christy were awesome for support when I owned mine. I remember several times trying to find a part, or other info and John would go pull the original plans out of the vault and give me the answer all while on the phone with him.[/quote]

Yes, John is definitely the man. Unmatched knowledge and an unbelievable resource.
He always has time to talk to you and has a memory like a steel trap.

Frank