I have read mixed results with the 6.4 cam but it does seem like the easiest route to take. You have done it with the stock springs with no issues? I was planning to put a set of springs on it anyway and get it tuned. I am not concerned about the MDS lifters going bad so much as making more tuned power without the MDS. The people I have talked to all said they make more power without the MDS. This thing is not a driver where I am concerned about fuel mileage so ditching the MDS really doesn't hurt my feelings.