Will having a mod my friend doesn't have, crash him/us?

Say I have the bigger ship thing, or an item he doesn't have, if I join his server, will we crash?
If he joins mine?

Can he see the stuff , the bigger ship, etc.?

 

Turns out, it won't crash but whatever you use is invisible to them.

 

If it's a custom ship it wont crash outright, no idea what will happen if you try to go there though, never tried.

If it's a stat edit to a vanilla item (still uses vanilla graphics), it will be fine.

 

Thats because their starbound game doesn't have the files, so they have no clue what the item is and farts a brick in protests.