I'm equally interested.
Are there any spring replacement packs for sale?
I've been told to get a few extractors, that they will fail, but I haven't broken one yet.
Probably because I don't shoot them much anymore.
If your M1 is GI or constructed of GI components, and put together properly, no additional parts need to be sought.
If you buy an extra bolt etc. you are stockpiling parts you do not need.
An additional set of GI springs (NOT aftermarket, even from Wolff) is always nice to have around, but is not required.
The "extractor failing" is a NON issue. The M2 version (select fire) in Korea was spitting rounds like crazy day in and day out. The soldiers were not complaining.
If you are the type of individual that takes weapons apart to the bone, maybe some extra pins are in order.
The GI configuration M1 carbine is one of the nicest shooting rifles the U.S. ever had around, so NEVER sell it. You will regret it for the rest of your life if you do.
I have no real experience with non GI carbines, so all this info pertains only to GI rifles.