"Yes, there are different jets
"Yes, there are different jets but I do not personally have a listing of what you should be using at that altitude.
Any OMC/BRP dealer can sort out what you need.
Additionally, because it is now more difficult for your motor to breathe properly you are most likely going to have to "re-prop" your boat.
I suspect, at minimum, you are going to have to drop down at least 2" in pitch.
YES, you are going to lose some top end speed (in theory), but since your motor CAN'T turn the larger prop you aren't really losing something that you currently have.
There is nothing you can do that will make it run exactly how it did when you were closer to sea level - just going to have to live with that - but you can maximize it's performance for your new location..."