I would not bother taking it to Apple unless the current board has failed. They do not do upgrades.
Apple will only replace a defective part "in kind." That has been their policy as long as I have participated here (20+ years). They won't upgrade it to "bigger/faster." If you have a board replacement done, Apple will use a new board with the exact specs of the one they remove.
If you need faster performance, sell or trade in your current Macbook Pro and get a new one with the specs you need. Remember, storage and RAM are now integral with the logic board and not even the deities on Mount Cupertino can upgrade those after the computer leaves the assembly line. Buy the performance you need in three years NOW.