Replace logic board on MacBook pro retina early 2013 i have to replace my broken logic board on my MacBook Pro retina display early 2013. I am wondering what alternatives I have: since I have to replace it, can I also speed it up with something from the late 2013 or 2014 series? Where can I order replacements? I tried fixit.com, but they only have a used 8GB board.
Inquire at [Other World Computing].1 They will know which part and why. 

The classic resource for complete info on every Apple machine is everymac.com.