Originally Posted by GeorgNihilus
Enter KSE, look for your savegame nš, then follow branch to NPC-Bastila-Appearance, clic on the right box and choose P_FEM_MJ_SML_01 or so. Clic on Change appearance button. Do the same with her portrait, Portrait field, look for Mara's file. When you are done with both editions, clic in apply changes (saves changes).
Adding that, you will have to edit her full body portrait (po_pbastila3.tpc) to fix all the portraits.
that's it for Bastila as Mara Jade ...
Don't do this if you already have Mara as PC unless you want twin sisters
Thanks for the great tip!