I highly recommend this board reivew book written by Steve Simmons, D.O. He trained in family medicine, is doing a sports medicine fellowship, and was a former OMM teaching fellow. It's in depth enough for all three parts. It's available at:
I think that the performance based COMLEX is a good idea. The USMLE people are doing it too. After observing the clinical skills of some residents, I get the feeling most med students blow off clinical skills labs in med school.
I here that it is under consideration. They did a survey of DO students a couple of years ago and most were actually against a computer based exam and wanted to keep paper and pencil----I don't know why...