I am planning to order a small quantity of 106mm forged pistons from a well-known manufacturer in the USA.
Sounds promising. Will they also supply good quality piston rings? It seems the rings are more difficult to source than the pistons.
Are you sending a SR41 piston or a SR43 piston for a sample. Unless I'm mistaken the SR43 piston has small valve recesses cast or machined into the piston crown to make extra room for the valves due to the SR43 longer stroke. I'd expect the SR43 piston could be used in the SR41 (with maybe a very slight reduction in compression ratio) but not the reverse due to possible valve contact.
What company are you using?